This Chapter focuses on what may be termed as metapsychology of yoga. Yoga system postulates a new model that could bring a paradigmatic shift in the way we study and understand human nature and the basic assumptions underlying it. The chapter discusses the scope and methods, the psychological processes involved, the existential context of human functioning, and the implications and application of yoga psychology. All these stated in a sutra form concisely in 333 postulates. It further goes on to discuss whether psychology based on yoga postulates is inclusive as suggested, and whether it is pessimistic as some others have depicted it. Yoga psychology may be considered the foundation and the base of what may be called Indian psychology. It can be a viable alternative to the currently dominant mechanist, reductionist, and computer models of the mind. Indian psychology is more inclusive than Western psychology in its methods and scope. The primary focus of Indian psychology is on the person rather than the object of experience. The emphasis is on the mental rather than the physical aspects of the person.