School bullying is a complex issue with far-reaching negative consequences for students' well-being and development. It's rarely caused by a single factor but rather a combination of interconnected elements stemming from various aspects of a child's life and environment. Here are some of the main causes, drawing upon common understandings of the issue:  

1. Family Influences:

Lack of Parental Supervision and Involvement: When parents are absent, uninvolved, or unaware of their children's social interactions, children may lack guidance on appropriate behavior and be more susceptible to engaging in or becoming victims of bullying.    
Exposure to Violence and Aggression at Home: Children who witness or experience violence within the family may learn that aggression is an acceptable way to resolve conflict or exert power, increasing their likelihood of becoming bullies.    
Inconsistent or Harsh Discipline: Unclear boundaries or overly punitive disciplinary measures can foster resentment, insecurity, and a desire for control in children, potentially leading them to bully others. Conversely, a complete lack of discipline can also result in a lack of understanding of social norms and consequences.
2. Social and Cultural Factors:

Media Influence: Exposure to violence and aggression in movies, video games, and online content can desensitize children and normalize aggressive behavior, potentially influencing their interactions with peers.    
Peer Pressure and the Desire for Social Status: The need to fit in and gain acceptance within a peer group can sometimes lead students to participate in bullying behavior to prove themselves or avoid being ostracized.
Societal Norms and Beliefs: In some cultures or subcultures, aggression or dominance might be implicitly or explicitly valued, contributing to a climate where bullying is more likely to occur. Misconceptions about power and strength can also play a role, with bullies believing that their actions elevate their status.    
Bystander Effect and Lack of Intervention: When peers or adults witness bullying and fail to intervene, it can reinforce the bully's behavior and make the victim feel isolated and helpless.
3. Individual Factors:

Lack of Empathy and Social Skills: Students who struggle to understand or share the feelings of others may be less likely to recognize the harm caused by their bullying behavior. Poor social skills can also lead to frustration and resorting to aggression in social situations.    
Low Self-Esteem (in both bullies and victims): Bullies may use aggression to mask their own insecurities and feel powerful by putting others down. Victims, on the other hand, may have pre-existing low self-esteem that makes them more vulnerable targets.    
 
Differences and Perceived Vulnerabilities: Students who are perceived as different due to their appearance, socioeconomic status, academic performance, or any other characteristic can become targets of bullying.    
Attention-Seeking Behavior: Some students may engage in bullying to gain attention from peers or even adults, albeit in a negative way.    
4. School Environment Factors:

Inadequate Supervision: Insufficient adult supervision in areas where bullying is likely to occur (hallways, playgrounds, cafeterias, online spaces) provides opportunities for bullies to act without consequence.    
Unclear Rules and Inconsistent Enforcement: If school policies against bullying are vague or not consistently enforced, students may not understand the seriousness of their actions or fear punishment.
Negative School Climate: A school environment characterized by competition, exclusion, or a lack of respect can create a breeding ground for bullying.
Lack of Anti-Bullying Education and Programs: Schools that do not actively teach students about bullying, empathy, conflict resolution, and how to report incidents may fail to equip them with the skills and knowledge to prevent and address bullying.