Different disciplines ask why public sector corruption occurs, addressing diverse phenomena. However, how different approaches and factors at micro, meso, or macro levels relate to each other in causally complex, context-dependent ways is seldom theorized. This article develops an integrated "Corruption Hexagon" model with six dimensions. The analytically relevant context provides a not directly causal background that influences the interplay of the pressure to act corruptly, the opportunity to benefit from corruption, the capability to exploit the opportunity, the supply of corruption, and the rationalization of one's corrupt behavior. Using secondary data from 23 European countries, we operationalize the Hexagon to explain differences in procurement-related corruption risks. Results corroborate the Hexagon's expectations: whereas the circumstances enable corruption, their interplay with personal characteristics or rationalization triggers corruption. The Hexagon offers a flexible, context-dependent, complexity-informed model for cumulative research integrating different methods and theoretical assumptions about the agency underlying corruption.