How and why crime rates vary across different societal and cultural contexts has been a perennial question within criminological research. Numerous studies have emerged in recent years responding to calls for criminology to examine the cross-cultural relevance of contemporary theory. While many of these studies have made significant advances, a great deal of work remains to be done in the development of theory, measurement, and methods. The present article examines the state of cross-national criminological research, including a discussion of challenges in examining key theoretical questions. Promising avenues for overcoming issues with data and developing key theoretical perspectives to better assess how social processes explain cross-national variations of crime are discussed.