Traumatic brain injury (TBI) is a significant concern in the veteran population, and the Department of Veteran Affairs (VA) has devoted substantial healthcare resources to the rehabilitation of veterans with TBI. Evaluating the outcomes of these rehabilitation activities requires measuring whether they meaningfully improve veterans' lives, especially with regard to community and vocational participation, which are strongly linked to perceived quality of life. In January 2010, the VA Rehabilitation Research and Development Service convened an invitational conference focused on outcome measurement in rehabilitation with a specific focus on veterans' community and vocational participation. This article reports on the working group, addressing the issues of conceptualizing and operationalizing such participation outcome measures for veterans with TBI; we discuss conceptual models of participation, review participation subdomains and their instruments of measurement, and identify current research issues and needs. Two avenues are identified for advancing participation measurement in veterans with TBI. First, we describe suggestions to facilitate the immediate implementation of participation measurement into TBI clinical practice and rehabilitation (cont) research within the VA healthcare system. Second, we describe recommendations for future VA research funding initiatives specific to improving the measurement of participation in veterans with TBI.