This article describes the development and validation of a 14-item, self-report measure of residents' perception of control over the institutional environment. Two studies of residents from a variety of institutional settings provided evidence of reliability and validity. Evidence of scale construct validity included the finding that residents living in a less restricted setting had higher Perceived Control Scale scores than residents of a more restricted setting. Another set of validity findings showed that the Perceived Control Scale was significantly associated in the expected direction with measures of locus of control, self-esteem, fatigue, vigor, and depression. The prediction that nurses' ratings of hospital patients' health would be related to the patients' scale scores was not confirmed. An intervention study showed that after participating in a workshop designed to increase perceived control over the institutional environment, residents of a retirement facility had significantly higher Perceived Control Scale scores than residents in a control group. The individuals participating in the workshop also had significantly better scores on theoretically related measures of well-being such as depression, vigor, and life satisfaction.