Secondary conditions are considered a direct consequence of having a disability, and many are presumed to be preventable. Although a few researchers have noted that people with disabilities are exposed to several secondary conditions, including pain, fatigue, depression, and obesity, what is lacking in the literature is a conceptual framework for understanding the antecedents, risk factors, and consequences of secondary conditions. To move the rehabilitation and public health professions toward a more unified approach to understanding and managing secondary conditions as well as distinguishing them from chronic and associated conditions, this article proposes a set of criteria for defining secondary conditions and a conceptual model that considers the potential factors associated with their onset, impact, severity, and management. © 2011 American Physical Therapy Association.