The present study examines the individual and joint contributions of personality, situations, and relationship contexts as they shape risky sexual behaviors. Data on 7,511 discrete sexual events collected from a community sample of 1,946 young adults were analyzed with multilevel modeling. Results showed that meaningful between-persons differences in risky sexual behavior exist and that these differences are predictable in theoretically reasonable ways by interindividual differences in personality. However, the majority of variance in risky behaviors was at the within-person level and could be reliably explained by within-person changes in personality, the situation, and the relationship context. Finally, personality interacted with context such that personality more strongly predicted risky behaviors in contexts that were ostensibly novel and ambiguous. Together these results suggest that risky Sexual behaviors cannot be understood in a static, typical, or decontextualized way but rather must be viewed as a complex product of the person, the situation, and the relationship context.