This article presents the PTSI (Person x Task x Situation Interaction) theory of creativity. The theory deals with the creative person, the deployment of creativity in tasks, the ecological context in which this deployment takes place, and the types of creative products that result. The theory draws upon a wide range of previous work. The article opens with an introduction to some major issues. Then it moves on to a review of past theoretical frameworks for understanding creativity. Next, it reviews various theories and models of creativity. Finally, it presents the PTSI theory. The attributes of the person system are personality, thinking styles, attitudes, cognitive processes, and knowledge. The task system represents the extent to which different aspects of a task encourage or discourage creative work. The situational context involves different hierarchically embedded levels of ecological context. The interaction between person, task, and situation produces different deployments of creativity and different types of creative contributions. After the theory is described, its motivation and then some of its strengths and weaknesses are considered, and future research is suggested to test the PTSI theory. The theory offers a somewhat more comprehensive view of creativity than many theories in the past have.