A sibling relationship is one of the longest familial attachments. During childhood and adolescence, siblings spend more time together than they do in most other relationships. Through relationships and interactions with each other, brothers and sisters make significant contributions to one another’s overall development. Since the 1990s, there has been a growing number of research studies examining the effects of sibling relationships on the development of children. This research has found that positive sibling relationships and interactions can facilitate important skills in social and cognitive development (Cicirelli, 1995).

Children with amicable sibling relationships are more likely to have a higher sense of well-being (Tucker et al., 2013), and positive sibling relationships help children develop social skills and emotional support (Stormshak et al., 1996), as well as protecting children from family adversities and unfavorable life events (Gass et al., 2007). In contrast, negative sibling relationships can have long-term adverse effects (Dunn & Herrera, 1997). One of the most common negative behaviors among siblings is sibling bullying. Being a victim of sibling bullying in childhood has been shown to adversely affect children’s overall development, and it has been associated with poor mental health; combined, these can lead to problems at school and aggression towards peers (Bank et al., 2004; Criss & Shaw, 2005).

According to Wolke et al. (2015), sibling bullying is any unwanted aggressive behavior(s) by a sibling that involves an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated; bullying may inflict harm or distress on the targeted sibling including physical, psychological, or social harm.

Unlike in a peer relationship, children born into a family do not have the freedom to choose their siblings. Additionally, siblings are rarely equal in age, height, physical strength or psychological makeup, so there is often a power imbalance. Siblings often spend a lot of time together without an adult being present, which creates opportunities for frequent and repetitive bullying among siblings. Moreover, the intimate familiarity brought about by living together helps siblings know exactly how to incite or annoy their siblings (Ensor et al., 2010).

Several studies have highlighted the potentially harmful effects of sibling bullying, and noted that it should not be considered normal. However, in many families, sibling bullying happens frequently (Tucker et al., 2013; Wolke & Skew, 2011; Toseeb & Wolke, 2021). Unlike bullying behaviors by adults or unfamiliar children, bullying among siblings is sometimes not seen as bullying; instead it is viewed as a fight, or a quarrel among siblings. As a result, sibling bullying and its impact often go unnoticed, despite having the same negative consequences as any other bullying behavior (Kettrey & Emery, 2006).

Survey research on sibling bullying has been conducted in many countries. Duncan’s (1999) study, conducted in the US, showed that only 3% of children were considered to be victims only, while 28.6% were both victims and bullies. Research by Wolke and Samara (2004), conducted in Israel, found that 16.5% of children were bullied verbally, or both verbally and physically weekly or several times a week. Research by Wolke and Skew (2011) in the UK regarded a behavior as bullying if it occurred at least four times in the past six months. Results from that study showed that 16% of children were victims only and 33.6% were both victims and bullies. Also, physical bullying (e.g. hitting, kicking, pushing) and verbal bullying (e.g. name calling) are frequent types of sibling bullying. A study on children aged 8 to 12 years old in Indonesia showed that the percentage of victims of sibling bullying (24.8%) was higher than that of peer bullying in schools (20.8%), which showed that parents and teachers need to be highly concerned about domestic bullying (Borualogo & Casas, 2021).

Several factors have been found to influence sibling aggression. McHale et al. (2012) found that when parents spent more time doing daily activities with their children and adolescents, sibling relationships were more positive. More attentive and involved parents also helped reduce aggressive behaviors among siblings. The presence of parents made siblings less likely to fight because of the parents’ increased care and supervision. Parrenas’s study showed that children of migrant mothers may be especially prone to anger, feelings of being abandoned or unloved, confusion, and worries (Parrenas, 2008). The effect of parental migration varies across different countries. Graham and Jordan (2011) have examined psychological difficulties of children under 12 years old in Indonesia, the Philippines, Thailand, and Vietnam, living with both parents in the same communities and children had one or both parents working abroad. The results showed that in Indonesia and Vietnam, children of migrant fathers were most likely to suffer emotional disorders (Graham & Jordan, 2011). In Ethiopia, parental migration does not have a significant effect on children. However, parental migration reduced health outcomes of children in India, Peru, and Vietnam (Nguyen, 2016).

Based on the above research results, we assume that the frequent absence of one parent, the father or mother, can escalate the situation of sibling bullying in the family.

Family size can also be a factor in sibling bullying. In families with more children and brothers, aggression was higher (Bowes et al., 2014; Tucker et al., 2013). Research by Toseeb et al. (2020a) showed that sibling bullying occurred more frequently in households with more children. We will also examine the relationship between a child’s number of siblings and bullying to test this claim.

Research results on the effect of the family’s socioeconomic status (SES) on sibling aggression are inconsistent. While research by Eriksen and Jensen (2009) showed that families of a lower economic status had a higher level of sibling aggression, Toseeb et al.’s (2020a) research showed that there was no difference in sibling bullying between low-income households and high-income ones. This demonstrates that sibling bullying is common, regardless of the family’s socioeconomic status (Toseeb et al., 2020a).

The mixed results of research on the relation between SES and sibling aggression allowed us to assume that another factor, which is the organization of the child’s living space, might be related to sibling aggression and bullying. There are families, with difficult economic conditions, unable to arrange a separate room, or a separate bed for each child. On the other hand, there are also families that can afford to provide children with their own spaces, yet fail to do so. Not having their own space can cause children to clash, leading to conflict. In this study, we also try to find out whether having their own space, such as own rooms, or own beds, could reduce sibling bullying.


Peer bullying has also been studied in many countries around the world. In some studies, the percentage of children reporting that they were targets of peer bullying ranged from 12% (Wolke & Skew, 2011) to 16% (Wolke & Samara, 2004; Duncan, 1999). Similar to sibling bullying, peer bullying at school is a negative behavior that shows the ability of one or more students to intimidate, or harm, vulnerable students as a means of controlling and maintaining power. A behavior is considered bullying if it exploits the power imbalance between the bully and the victim repeatedly (Olweus, 1999). Sometimes the bullying’s power imbalance is not only physical, so bystanders cannot recognize it. However, it can be considered as bullying when the victim feels threatened or wants such behavior to stop (Piquet, 2017).


Several researchers believe that there is a connection between family and non-family relationships and sibling victimization, peer victimization, and well-being. Social learning theorists argue that children learn specific behaviors by observing relationships between their parents and siblings and then generalize these behaviors in their interactions with peers and friends (Putallaz, 1987). Other researchers argue that the stable temperament and characteristics of children tend to elicit similar responses in different relationships; thus, there is a similarity between siblings in families and peer behaviors at school (Gleason et al., 2005). A study conducted by Wolke and Samara (2004) on sibling and peer bullying showed that among sibling victimized children, more than 50% were also peer bullying victims. Duncan (1999) found that 60% of peer bullying victims were being bullied by their siblings. Menesini et al. (2010) found that being a victim of sibling victimization was correlated with being a victim of peer bullying, with correlation coefficients for boys and girls at .35 and .38 respectively. Ensor et al. (2010) argued that sibling conflict was present in all families; however, when the conflict between siblings became severe, repeated, and intentional bullying behaviors, it could profoundly impact peer relationships.

Research on potential consequences of bullying has found links with behavioral, emotional, or health problems (Hawker & Boulton, 2000; Wolke et al., 2000, 2001; Gini & Pozzoli, 2009). Studies have found that sibling victimization and peer victimization escalated poor adaptation, associated with increasing rates of behavioral or emotional problems, and reduced well-being (Duncan, 1999; Wolke & Samara, 2004; Wolke & Skew, 2011).

There has been a lot of evidence of a relation between sibling bullying and negative aspects of mental health (Toseeb et al., 2018, 2020b; Liu et al., 2020, 2021; Lopes et al., 2019; Tucker et al., 2013). However, studies on the relationship between sibling bullying and the positive aspects of mental health are limited (Toseeb & Wolke, 2021). This study provides further evidence of the link between sibling bullying and subjective well-being, a positive aspect of mental health.


Vietnam has a high population density, most families have two or more children, and schools often have crowded classes. Although sibling bullying has been studied extensively in many countries (Duncan, 1999; Wolke & Samara, 2004; Wolke & Skew, 2011; Menesini et al., 2010; Borualogo & Casas, 2021), there is almost no research on this subject in Vietnam. Indeed, though sibling bullying is a global issue, its degrees and characteristics vary across countries. Interviews with some parents, waiting to pick up their children after school at the school gate, revealed that many parents in Vietnam were not aware that sibling bullying could cause the same negative consequences as other forms of bullying. Some believed that quarrels and fights were a kind of exercise that brings more coping skills to siblings. A father said: “It is normal for brothers and sisters to fight and cry, they have to practice in order to cope with others in the future” (father, 41 years old, Hanoi). A mother shared: “I have two children, my daughter is aggressive, my son is a coward, and is bullied by his elder sister all the time. I’m making him (younger brother) stronger, he’s too weak, it’s not good for him” (mother, 39 years old, Hanoi).

According to a 2020 report by the United Nations International Children’s Emergency Fund (UNICEF, 2020), about 68% of children from age 1 to 14 years in Vietnam experienced violence from their parents, caregivers, or other family members at least once. According to a survey by the Plan International Vietnam in collaboration with the UN Trust Fund in 2014, out of 3,000 students surveyed in Hanoi, more than 2000 (> 65%) reported they had been bullied in various forms (e.g., cursing, threatening, denigrating, humiliating, mugging). Many children did not share the troubles they encountered at school with their parents and/or relatives. This failure to share their troubles is believed to make these children feel anxious, depressed, and fearful of going to school (Nguyen, 2018). For victims of bullying, the consequences are diverse and include general expressions of fear, a fear-based desire to avoid school, depression, and thoughts of suicide (Khanh, 2016).

In Vietnam, there have been several studies on peer bullying (Khanh, 2016; Nguyen, 2018), but there have not been any studies on sibling bullying and its relationship with school victimization and well-being. This study is an initial exploration of the subject.


This study aims to answer the following questions: (1) whether or not there are differences in sibling victimization by sex, age, number of siblings in the family, a parent’s absence from the home due to employment, or a child’s privacy (i.e., has a private bedroom or bed) (2) the relationship between sibling victimization and peer victimization, and (3) the relationship between sibling victimization and a child’s well-being among Vietnamese children.

Based on social learning theory and the research results outlined above, we propose the following hypotheses: (H1) Boys are victimized more by siblings than are girls and older children are bullied less than younger children. Children whose parents work away from home are victimized more by siblings than those children whose parents do not work away from home. Children who do not have a private bedroom or a separate bed to sleep on are victimized more by siblings than are those who have their own bedroom or own bed; (H2) there is a positive correlation between sibling victimization and peer victimization; and (H3) there is a negative correlation between sibling victimization and well-being.



Participants were 1537 Vietnamese children attending public schools, age 10-14 years (M = 11.29, SD = 1.15), including 811 boys and 726 girls.


Permission to conduct the research in Vietnam was obtained from the Vietnam National Foundation for Science and Technology Development. Approval for the study was gained from the Scientific Department at the University of Social Sciences and Humanities, Hanoi (consent number: 334/HĐ-501.01-2020).

In Vietnam, there is no requirement for parental consent to allow children to participate in surveys conducted at school. However, approval for conducting the survey during school time was gained from the school administrators and classroom teachers. All children were informed that they were free to not answer the questions. The data were treated confidentially.

The survey was conducted in public schools in five provinces in Northern Vietnam – Hanoi, Ha Nam, Thai Nguyen, Son La, Bac Giang – and consisted of paper and pencil group surveys. The researchers were present in the classroom during the survey administration. Researchers explained the purpose of the survey to the participants, answered student questions, informed students that their responses would remain confidential, that nobody would have access to the data except the researchers, and that the students were allowed to stop participating in the survey at any point. Questionnaires contained no personally identifiable information. Surveys were collected by the researchers and afterwards data were entered into a spreadsheet.


The current study’s researchers participated in the third wave of the International Survey of Children’s Well-Being (ISCWeB) as representatives of Vietnam. The questions used for analysis in this study were part of the ISCWeB project’s questionnaire, which was a self-report questionnaire, include bullying items and a child subjective well-being scale, which were translated into Vietnamese following the guidelines for translation and cultural adaptation of the instruments, as was strictly required by the ISCWeB project.

Bullying items. The five items on bullying (two for siblings and three for school peers), corresponding to different behaviors used in bullying (e.g., hitting, calling by unkind names, excluding/ignoring). The response format was on a four-point frequency scale (0 – never, 1 – once, 2 – 2 or 3 times, and 3 – more than 3 times in the past month).

Children’s Worlds Subjective Well-Being Scale. The scale contained six items measuring cognitive subjective well-being (based on the Student Life Satisfaction Scale by Huebner, 1991). The response format was on a Likert scale from 0 (totally disagree) to 10 (totally agree), with higher scores indicating greater subjective well-being.

These tools were first used on Vietnamese children. However, this study does not aim to adapt the scale; thus we only briefly introduce the structure and the reliability of the scale.

Structure and reliability of the scale. Among the children surveyed, there were 109 children (7.1%) without siblings (Table 1). Since the study focused on sibling bullying, we analyzed (including factor analysis) only data from children with siblings (n = 1428, Msiblings = 1.89, SDsiblings = 1.26).

Table 1

Descriptive statistics (N = 1537) and EFA standardized factor loadings (N = 1428) for Bullying items

ItemFrequency of being bullied (%)Factor loadings
NeverOnceTwo or three timesMore than three timesDon’t have siblingFactor 1Factor 2
3. Hit by other children in school
(not including fighting or play72.515.
5. Left out by other children in your class71.915.
4. Called unkind names by other children in school57.814.69.418.2.695
1. Hit by your brothers or sisters
(not including fighting or play58.711.
2. Called unkind names by your brothers or sisters57.

[i] Note. Extraction method: principal component analysis; rotation method: Varimax with Kaiser normalization.

Principal component analysis was used to explore the factor structure of the Bullying and Children SWB scales. For the Bullying scale, there were two components with eigenvalues above 1, KMO = 0.69, and the two-factor solution explained 65.93% of the total variance. Factor 1 (33.31% of the variance) represents peer bullying, while factor 2 (32.62% of the variance) represents sibling bullying. The descriptive statistics for each item and EFA standardized factor loadings for the Bullying scale are presented in Table 1.

For Children SWB, only one component with KMO = 0.91, the one-factor solution, explained 73% of the total variance (Table 2).

Table 2

Descriptive statistics and EFA standardized factor loadings for Children SWB items (N = 1423)

ItemMSDOne factor
3. I have a good life8.092.51.883
5. I like my life8.092.54.881
6. I am happy with my life8.142.53.873
1. I enjoy my life7.942.45.866
2. My life is going well8.322.29.803
4. The things that happen in my life are excellent7.222.77.798

[i] Note. Extraction method: principal component analysis; rotation method: Varimax with Kaiser normalization.

Cronbach’s α of Children SWB is high (α = .92), and Cronbach’s α of Bullying is acceptable (α = .68, α = .60 for sibling bullying, and α = .61 for peer bullying).

Survey questions also included demographic information such as age, gender, and the number of brothers and sisters children have. Additionally, children were asked the following questions:

In the last year did either of your parents live or work away from home for more than a month? (The response options were 1 – No; 2 – Yes, in another part of Vietnam; 3 – Yes, in a different country).

Do you sleep in a room on your own or do you share a room? (1 – I sleep in a room on my own; 2 – I sleep in a room that I share with other people).

Do you have your own bed? (1 – Yes, I have my own bed; 2 – No, I share a bed; 3 – No, I don’t have a bed).


Data from completed surveys were entered into IBM SPSS Statistics for Windows, Version 22.0 for analysis. The data were analyzed using both descriptive statistics (frequency, mean score, standard deviation, average score) and inferential statistics (t-test, one-way ANOVA, Pearson’s correlation).

To test hypothesis H1 we used the t-test and one-way ANOVA. To test hypotheses H2 and H3 we used Pearson’s correlation.



Using “hit by siblings” and “called by an unfriendly name” as qualifying criteria for victimization, after calculating the number of times a child is bullied by counting the total number of times the child was hit by siblings and called by an unfriendly name, less than half of children (46.2%) reported they were not bullied by their siblings, while the more than half (53.8%) reported being bullied by their siblings at different levels (Table 3).

Table 3

The situation of sibling victimization in the past month (N = 1428)

Frequency (%)MSD
NeverOne to two timesThree to five timesSix times or more

[i] Note. Mean equals the average number of times children were bullied by siblings in the past month.

The t-test for independent samples was used to compare the number of times a child was bullied by siblings by the following criteria: gender, age, residential location, the number of siblings in the family, whether the child’s mother or father working away from home, and whether the child has a private bedroom or bed. The results are shown in Table 4.

Table 4

Differences between the average results of the sibling bullying’s frequency (N = 1428)

VariableGroupsMSDt(df)pCohen’s d
GenderBoy (n = 751)1.561.870.97 (1426).332.05
Girl (n = 677)1.461.83
AgeFrom 10 to below 12 (n = 681)1.671.903.07 (1426).002.16
From 12 to 14 (n = 747)1.371.79
Mother working away from homeaMother working far away in other provinces (n = 158)
Mother not working far away from home (n = 1251)
1.51 1.511.85 1.820.01 (1407).995.00
Father working away from homebFather working far away in other provinces (n = 292)
Father not working far away from home (n = 1113)
1.82 1.441.91 1.833.10 (1403).002.20
Children having private roomcChildren sharing bedroom with others (n = 496)
Children having private bedroom (n = 924)
1.74 1.391.94 1.793.43 (1418).001.19
Children having private beddChildren sharing bed with others (n = 389) Children having private bed n = 10221.76 1.411.91 1.823.22 (1409).001.19

[i] Note. a missing 19 (1.3%); b missing 23 (1.6%); c missing 8 (0.5%); d missing 17 (1.2%).

The results presented in Table 4 partly support hypothesis H1.

Children from 10 to under 12 years old were bullied by siblings more than those from 12 to 14 years old (t(1426) = 3.07, p = .002). Children whose fathers were working away from home were bullied by siblings more than children whose fathers were not working far away from home (t(1403) = 3.10, p = .002). Children who share a bedroom or bed with others are also victimized more by siblings (t(1418) = 3.43 for bedroom and t(1409) = 3.22 for bed, p = .001). The impact of all the above factors is significant, but only at low levels (effect size Cohen’s d ≤ .20).

From the results presented in Table 4, some statements in H1 are not supported; in particular, there is no statistically significant difference, showing no significant impact on sibling victimization, between boys and girls (t(1426) = 0.97, p = .332), and between children who do and do not have a mother working away from home (t(1407) = 0.01, p = .995).


Each type of sibling bullying is positively correlated with peer bullying behavior (see Table 5).

Table 5

Pearson correlation (r) between bullying behaviors (N = 1428)

Kind of bullying1234
1. Hit by your brothers or sisters
2. Called unkind names by your brothers or sisters.40**
3. Hit by other children in school.28**.18**
4. Called unkind names by other children in school.13**.25**.33**
5. Left out by other children in your class.17**.23**.36**.30**

[i] Note. **p < .01.

Using ANOVA to compare the frequency of peer victimization and well-being among groups of children, including children without siblings, the results show that children without siblings have lower well-being than those with harmonious siblings, but higher than those having sibling victimization of different levels. The more bullied children are by their siblings, the more often they are bullied by peers (F = 18.52, p < .001) (see Table 6).

Table 6

Comparison of frequency of peer victimization and well-being among groups of children (N = 1537)

VariablesWithout siblings (n = 109)Having siblings, Having sibling victimization of different levelsFp
Never (n = 660)One to two times (n = 355)Three to five times (n = 328)Six times or more (n = 85)
Peer victimization1.621.081.712.452.9318.52< .001
Well-being8.068.377.827.477.1749.58< .001

[i] Note. Test of homogeneity of variances with p < .001.

The results in Table 6 also show that the more often they are bullied by their siblings, the lower is their well-being (F = 49.58, p < .001). This is also confirmed by analyzing the correlation between sibling victimization and peer victimization (r = .30), between sibling victimization and well-being (r = –.19), and between peer victimization and well-being (r = –.21) (see Table 7).

Table 7

Pearson correlation (r) between each kind of bullying and subjective well-being (N = 1428)

1. Being bullied by siblings
2. Being bullied by peers.30**
3. Subjective well-being–.19**–.21**

[i] Note. **p < .01.

The results in Tables 5, 6, 7 support hypotheses H2 and H3; namely, there is a positive correlation between sibling victimization and peer victimization, and there is a negative correlation between sibling victimization and children’s well-being. Children who were not bullied by siblings have the highest well-being. Children who were bullied most often by siblings had the lowest well-being.


The 53.8% of children with siblings in this study who reported being bullied by siblings at different levels is higher than the 31.6% in the study by Duncan (1999) in the US, but quite similar to the result of 49.6% reported by Wolke and Skew (2011) in the UK.

The current research results show that children aged from 10 to under 12 are bullied more than those from 12 to 14 years old. This result is similar to the results for children aged 10 to 15 surveyed in the US and UK that showed the number of children being bullied decreased with increasing age (Duncan, 1999; Wolke & Skew, 2011).

We expected to find higher levels of sibling victimization among boys than girls, but the results show no statistically significant differences between boys and girls. This finding is neither consistent nor inconsistent with previous research in this area, as other studies have failed to show a consistent result for gender differences. Duncan (1999) found that boys are victims of sibling bullying more often. However, the research results of Wolke and Skew (2011) showed that boys were often bullies or both victims and bullies, while girls were likely to be victims only. Research by Menesini et al. (2010) showed that, in general, younger children were more likely to be victims of older brothers.

An interesting finding in this study is that children whose fathers do not live most of their time at home because they work far away from home (in another province) were bullied more by siblings than children whose fathers work not far from home. Meanwhile, mothers’ working away from home did not have a significant impact on sibling victimization rates. This difference may be due to the fact that in Vietnam, the father is usually the head of the family who is responsible for maintaining order and enforcing rules, while the mother is typically in a role that is more affectionate and less strict with the children. It appears that the absence of a father can impair the family hierarchy and discipline system, and thereby increase sibling bullying. A study by McHale et al. (2012) showed that when parents spent time doing daily activities with their children, adolescent sibling relationships became more positive. It also indicated that more attentive and involved parents also help control and mediate aggressive behaviors among siblings. However, this study did not explore the differences between the roles of the father and mother separately.

It appears from the results of this study that children sharing a bedroom or bed with others, including with siblings, can raise conflicts and aggression among siblings. This could be related, however, to a difficult economic condition of the family. The fact that children sharing a bedroom or bed with others are bullied more by siblings supports the findings of Eriksen and Jensen (2009), in part, that the degree of aggression among siblings was higher in families of low socioeconomic status.

The positive correlation between sibling victimization and peer victimization in this study, once again, supports the well-established results that the experiences children have with their siblings affects their relationship with peers (Brody, 2004; Wolke & Samara, 2004), and being bullied by siblings is significantly related to being a victim of peer bullying at school (Menesini et al., 2010).

An interesting finding is that the group of children without siblings was bullied more by peers than those having a supportive sibling relationship, but bullied less than children who were exposed to sibling bullying. This finding supports the assumption that having siblings can be both a protective and risk factor, depending on the quality of the relationships among siblings. Positive sibling relationships help children develop social skills and protect them from difficult life situations (Gass et al., 2007). In contrast, negative sibling relationships can lead to problems at school and aggression with peers (Bank et al., 2004; Criss & Shaw, 2005).

Similarly to previous studies (Duncan, 1999; Wolke & Samara, 2004; Wolke & Skew, 2011), the current study also found a negative correlation between sibling victimization and well-being. Children with harmonious relationships with siblings who never experienced sibling bullying had the highest well-being, higher than those with no siblings. The group of children who were regularly bullied by siblings had the lowest well-being. This result is consistent with the findings of previous research studies. Criss and Shaw (2005) found that negative sibling relationships reduced children well-being. The study of Tucker et al. (2013) showed that children with positive sibling relationships were more likely to have higher well-being, because such siblings provided guidance, support, sharing and companionship.


Over half of children with siblings in this study (53.8%) reported varying levels of sibling victimization.

The research results partly support H1, namely: (against the hypothesis), there was no statistically significant difference between boys and girls; however (supporting the hypothesis), younger children were bullied more often than older children. (Supporting the hypothesis) the group of children whose fathers worked away from home were more bullied by their siblings, while (against the hypothesis) mothers who worked away from home had no significant impact on sibling victimization. (Supporting the hypothesis) the group of children who have to share a bedroom or bed with others were bullied more by siblings.

H2 was supported in full. There was a positive correlation between sibling victimization and peer victimization. The group of children having harmonious sibling relationships were least bullied by their peers. In contrast, the group of children who were most frequently bullied by their siblings were most bullied by their peers.

The results confirm H3. There was a negative correlation between sibling victimization and well-being. The group of children with harmonious sibling relationships had the highest well-being. The group of children who were regularly bullied by siblings had the lowest well-being.

Thus, the quality of sibling relationship appears to play an important role and affects the relationship with peers and children’s well-being. Therefore, parents need to be attentive to discovering and preventing sibling bullying, and building positive, harmonious and mutually supportive relationships among siblings. In addition, attention should be paid to the relationship between home and school, to prevent the development of sibling victimization and prevent it from spreading to school as peer victimization.


This study has some limitations. Firstly, the study only examined children in a narrow age range, from 10 to 14 years old, and only focused on victimization, without investigating bullying behaviors. Secondly, the research has not yet clarified the factors associated with sibling bullying such as parents’ behaviors toward their children, psychological atmosphere in the family, or personality characteristics of children.

Despite the limitations, this is the first study on sibling bullying in Vietnam with a fairly large sample size. Although assessment of sibling victimization through children’s self-reporting has limitations, it also has a certain scientific basis. As Piquet (2017) noted, power imbalances between children are not just physical, so sometimes observers cannot recognize them. When children themselves feel threatened, hurt, or ignored, and want such behaviors to stop, such behaviors are considered to be bullying behaviors and children are the most important persons to judge these consequences.


It is necessary to conduct further studies in Vietnam to resolve the above limitations. Firstly, it is necessary to expand the research scope to younger and older children, to detect groups of children who may be bullied at a young age, and to determine the age trend related to sibling bullying. Both bullying and victimization behavior types should be explored to clarify the situation of bullying, as most studies showed that very few children are victims only; most of them are both a victim and a bully in sibling relationships (Duncan, 1999; Wolke & Samara, 2004; Wolke & Skew, 2011). Last but not least, it is important to learn more about the characteristics of parent-child relationships and children’s personality traits and their relations to sibling bullying, in order to improve the ability to predict and prevent the development of sibling bullying.