Contemporary trends in social service delivery systems require human service agencies to engage in greater levels of advocacy to reform structures and protect programs that serve vulnerable populations. Objective: The purpose of this study was to develop an instrument to measure the policy advocacy behavior of nonprofit human service agencies. Method: Organizational demographic and policy advocacy behavior data were collected from 43 nonprofit human service agency executive directors. Results: The researchers determined that the Policy Advocacy Behavior Scale evidenced adequate reliability and validity. Conclusions: The Policy Advocacy Behavior Scale shows promise as a tool to inform future research on social work practice models that integrate policy advocacy methods. (Contains 3 tables.)