有四个主要的欺凌行为的类型：物理，情感/社会、语言、（2003 Fox和博尔顿，），和/或网络欺凌（薛拉斯，2002）。身体欺负的例子包括打击，踢，偷，打，或破坏别人的财物。言语欺凌可以是戏弄，骂人，八卦，或威胁。情感的社交欺凌可以散布谣言关于某人，隔离某人，或故意留下某人（C. Graves，个人通信，2010年4月16日）。网络欺负或欺负在线”（Sheras，2002，p. 55）已经成为一个新的问题，孩子在手机和电子邮件帐户，并参与社交网络首次在更年轻的年龄。
Bullying is defined as repeated negative actions over time directed at an individual (Olweus, 2002). The U.S. Department of Health and Human Services states that bullying involves an imbalance of power ("Stop bullying now," 2010). Seen as a continuum with teasing at one end and brutal bullying at the other. Another definition of bullying is "ongoing and frequent and includes verbal taunting, name-calling, threats, stealing, and acts of physical aggression" (Freedman, 2002, p. 5). Freedman (2002) stated that bullying also includes and "imbalance of power" (p.5) when the bully is older, larger, and has a high value of self. Bullying occurs within a social-ecological framework with the bully being a part of different environments such as school, home, peers, and community
There has only been one large-scale study conducted on bullying in the United States. Nansel et al. (2001) asked 15,686 6th-through 10th-grade students to self-rate themselves as victims or as bullies. The results found that 29.9% of the students indicated that they had been bullied or were bullies. Of the 15,686 students, 10.6% identified themselves as victims and 13 % indicated that they were bullies, and the remainder indicated that they have been both. In addition, this study found that there was a higher level of bulling in the middle school years compared to the high school years and that boys were more likely to be involved in bullying than girls. Boys are more likely to engage in physical bullying (Espelage, Bosworth, & Simon, 2001). Girls are more aggressive relationally
There four main types of bullying behavior: physical, emotional/social, verbal, (Fox and Boulton, 2003), and/or cyber-bullying (Sheras, 2002). Examples of physical bullying include punching, kicking, stealing, hitting, or damaging someone else's belongings. Verbal bullying can be teasing, name-calling, gossip, or threats. Emotional-Social bullying can be spreading rumors about someone, isolating someone, or leaving someone out on purpose (C. Graves, personal communication, April 16, 2010). Cyber-bullying or "bullying on-line" (Sheras, 2002, p. 55) has become a new problem as children are getting cell phones and e-mail accounts, and are becoming involved with social networks for the first time at much younger ages.