The effectiveness of efforts designed to address mental illness stigma will rest on our ability to understand stigma processes, the factors that produce and sustain such processes, and the mechanisms that lead from stigmatization to harmful consequences. Critical to such an understanding is our capacity to observe and measure the essential components of stigma processes. This article is designed to assist researchers in selecting or creating measures that can address critical research questions regarding stigma. Our conceptualization of stigma processes leads us to consider components of labeling, stereotyping, cognitive separating, emotional reactions, status loss, and discrimination. We review 123 empirical articles published between January 1995 and June 2003 that have sought to assess mental illness stigma and use these articles to provide a profile of current measurement in this area. From the articles we identify commonly used and promising measures and describe those measures in more detail so that readers can decide whether the described measures might be appropriate for their studies. We end by identifying gaps in stigma measurement in terms of concepts covered and populations assessed.