Most HIV-prevention funding agencies require the use of evidence-based behavioral interventions, tested and proven to be effective through outcome evaluation. Adaptation of programs during implementation is common and may be influenced by many factors, including agency mission, time constraints, and funding streams. There are few theoretical frameworks to understand how these organizational and program-related factors influence the level of adaptation. This study used constructs from both Rogers's diffusion theory and Rütten's framework for policy analysis to create a conceptual framework that identifies determinants hypothesized to affect the level of adaptation. Preliminary measures of these constructs were also developed. This framework and its measures assess organizational and program-related factors associated with adaptation and could serve as a model to assess implementation and adaptation in fields outside of HIV prevention.