Open educational resources (OER) have been developed to free students from the expense and instructors from the restrictions of commercial materials. There has been a wealth of empirical examination on numerous aspects of OER. The purpose of this narrative review is to synthesize and integrate the findings on OER in psychology to assist instructors in making informed decisions about course materials. Topics in this review were organized according to the Cost, Outcomes, Usage, and Perceptions framework. Results indicated that OER adoption yielded cost savings while generally having similar or better outcomes in terms of grades. Students typically reported similar use and perceptions of OER compared to commercial course materials. Resources for instructors interested in OER are described. Criticisms of OER, such as concerns about quality, are addressed as well as limitations of reviewed research and future directions for research and development of OER.