The accumulation of anecdotal accounts of copycat crime suggests that popular culture plays an important role in some instances and aspects of criminal behavior. However, there is little empirical research specifically examining the copycat effect on criminal behavior. Questions remain regarding the nature and extent of copycat crime, cultural influences that shape the copycat effect, the role and relevance of popular culture as a motivating factor for criminal behavior, and issues the copycat phenomenon raises for legal determinations of criminal responsibility. This paper reviews the research literature and contemporary case examples of copycat crime with attention to the influence of mass media technology on criminal behavior, the mechanisms of media-mediated crime, and the relevance of understanding the copycat phenomenon for determinations of criminal responsibility in insanity cases. An integrative theoretical model of copycat crime is proposed, a methodological framework for empirically investigating copycat crime is presented, and practical implications for understanding the role of the copycat effect on criminal behavior are discussed.