Stigma associated with being overweight or obese is widespread. Given that weight loss is difficult to achieve and maintain, researchers have been calling for interventions that reduce the impact of weight stigma on life functioning. Sound measures that are sensitive to change are needed to help guide and inform intervention studies. This study presents the weight self-stigma questionnaire (WSSQ). The WSSQ has 12 items and is designed for use only with populations of overweight or obese persons. Two samples of participants—one treatment seeking, one nontreatment seeking—were used for validation (N = 169). Results indicate that the WSSQ has good reliability and validity, and contains two distinct subscales—self-devaluation and fear of enacted stigma. The WSSQ could be useful for identifying individuals who may benefit from a stigma reduction intervention and may also help evaluate programs designed to reduce stigma.