Most scholars agree that candidates’ use of negative campaigning is based on rational considerations, i.e., weighing likely benefits against potential costs. We argue that this perspective is far too narrow and outline the elements of a comprehensive model on the use of negative campaign communication that builds on personality traits, values, social norms, and attitudes toward negative campaigning as complementary mechanisms to classical rational choice theory. We test our theoretical assumptions using candidate surveys for twelve state elections in Germany with more than 3,100 candidates. Our results strongly suggest that negative campaigning goes beyond rational considerations. Although benefit–cost calculations are the primary driver of the decision to attack the opponent, other factors are also important and enhance our understanding of why candidates choose to engage in negative campaign communication. Our findings have important implications for research on candidate attack behavior.