Process dissociation is a model for separating automatic and controlled contributions to responses in a single task. Although it was developed to separate conscious and unconscious uses of memory, researchers have increasingly found the model useful to answer questions in social psychology. This article reviews process dissociation studies with a focus on social psychology. It emphasizes the model's conceptual definitions of automatic and controlled processing and how those relate to procedures for estimating them. Process dissociation is contrasted with task dissociation, in which automatic and controlled processes are identified with implicit and explicit tasks. Current trends and future directions are identified, including the use of model testing procedures to compare competing theories of how automatic and controlled processes interact.