Objective: To conduct an initial validation of the mental health provider stigma inventory (MHPSI). The MHPSI assesses stigma within the service provider--client relationship on three domains--namely, attitudes, behaviors, and coworker influence. Methods: Initial validation of the MHPSI was conducted with a sample of 212 mental health employees and graduate student counseling interns. Scale conceptualization and development, content validation, and construct validation measures are discussed. Results: Preliminary psychometrics indicated good model fit for a three-factor multidimensional scale. Reliabilities were strong (coefficient as ranged from 0.83 to 0.93) and the global stratified a was 0.95. Evidence of construct validity supported the hypotheses about the accuracy of underlying constructs. Conclusions: The MHPSI appears to be a reliable and valid measure of mental health provider stigma. As social workers comprise the front lines of mental health service provision, the MHPSI may be a valuable tool for guiding agency trainings and social work education.