This article examines the conceptual basis for and methods used to assess school bullying, including the core bullying behavior elements of repetition, intentionality, and power differential and instruments needed to foster comparability across studies and to improve the precision of intervention capacity. Common bully self-report procedures (Olweus Bully/Victim Questionnaire, Olweus, 2004; Reynolds Bully Victimization Scale, Reynolds, 2003; The Bully Surveys, Swearer, 2001) are examined for the thoroughness with which they assess these core elements that distinguish bullying from other forms of peer victimization. It is concluded that bullying assessment can be enhanced by systematically including all core bully behaviors, more thoroughly examining sources of power differential between bullies and victims, and giving more attention to the dynamic nature of the bullying process. (Contains 1 table and 4 notes.)