Disability, one of modern society's greatest public health problems, affects individuals, families, and society. Understanding the complex process of disablement, therefore, is critical given the current and projected increases in disability. Terminology in the field of disablement continues to breed confusion and controversy across and within disciplines. This article discusses some of the major models that have been developed to guide physical therapy researchers and clinicians in their thinking about disablement. Emphasis is on physical disablement because of its central role in physical therapy research and practice. Detailed descriptions are provided for two disablement formulations. One was developed in the 1960s by sociologist Saad Nagi. The other is the International Classification of Impairments, Disabilities, and Handicaps, developed for the World Health Organization. Both can serve as the basic conceptual architecture for disablement research in physical therapy. Researchers and clinicians need a common vocabulary and language for thinking and speaking about the process of disablement, although it appears premature to reach consensus on any one conceptual approach. Physical therapists should play an active role in guiding future research and scholarship on physical disablement.