This article discusses conceptual issues and reviews knowledge about direct and buffering protective factors in the development of youth violence. Direct protective factors predict a low probability of violence, whereas buffering protective factors predict a low probability of violence in the presence of risk (and often interact with risk factors). Individual, family, school, peer, and neighborhood factors are reviewed. Heterogeneity of variables, measurement, contexts, study design, sample, and other characteristics limit generalizations. However, there were various evidence-based candidates for having a direct protective or buffering protective effect such as above-average intelligence, low impulsivity/easy temperament, enhanced anxiety, prosocial attitudes, high heart rate, close relationship to at least one parent, intensive parental supervision, medium SES of the family, sound academic achievement, strong school bonding, a positive school/class climate, nondeviant peers, and living in a nondeprived and nonviolent neighborhood. The probability of violence decreases as the number of protective factors increases (a dose–response relationship). Implications for future research and practice concern adequate research designs to detect nonlinear relationships; conceptually and methodologically homogeneous studies; differentiated analyses with regard to age, gender, and other characteristics; and greater integration of longitudinal correlational research with (quasi-)experimental intervention studies.