There have been some suggestions concerning the subject matter of Islamic psychology. It seems that these suggestions could not overcome the theoretical barrier for providing a subject matter for psychology. Some have considered the divine Spirit (Run) within the human as the subject matter, some others have regarded the Soul (Nafs)and still others, the divine creation of the human (Fitrah) as the candidates for doing the job. However, these suggestions could be challenged in different ways on being able to provide a suitable subject for scientific studies of psychology. The present essay is an introductory attempt to give an alternative. Accordingly, an alternative to the three abovementioned suggestions seems to be the important Islamic concept of Action. We can consider Action as the suitable subject matter for psychology. This is because action is so wide that it could cover all the humans whether believers or non-believers in God, whether their Fitrah is active or silent. An action, as it is used in the Islamic texts, refers to a behavior (being observable or non-observable) that is based on, at least, three kinds of foundations: cognition, emotion, and will. In addition to being a suitable subject for psychology, action is a key concept in referring to the human nature or identity.