This chapter describes the conceptual frameworks that provide conceptually compelling and empirically consistent accounts of the processes involved in maintaining obsessions and compulsions. Multicomponent treatment programs for obsessions and compulsions have been developed that involve sets of core procedures derived from the conditioning and cognitive behavioral models. The chapter also describes the “active ingredients” of these programs, their theoretical rationale, and evidence for their efficacy. It summarizes the theoretical models with direct relevance to empirically supported psychological interventions, such as conditioning model, and cognitive behavioral approaches. Exposure therapy involves intentionally confronting feared, but objectively safe, objects, situations, thoughts, and bodily sensations with the goal of reducing fear and other negative reactions to the same or similar stimuli in the future. Response prevention, a necessary accessory to exposure therapy, involves resisting urges to perform compulsive behaviors, overt and covert, that serve as an escape from obsessive fear.