The cost of course materials has continued to increase over time. Consequently, the use of Open Education Resources (OER) have become increasingly popular among instructors and institutions as a method of reducing college costs. Furthermore, using OER also reduces inequity in higher education by increasing the accessibility of course materials to all students. The present study investigated the efficacy of courses that used OER compared to those that did not on student achievement. Twenty-six articles were included in this meta-analysis. In OER courses, there was a higher completion rate with students earning at least a C (k = 12; d = 0.29) or at least a D (k = 6; d = 0.61). Furthermore, OER courses were associated with a higher course grade (k = 26; d = 0.17). These findings suggest that adopting OER can be a scalable, cost-effective, powerful, and successful method for educators and institutions to reduce the cost of attending college while bolstering student success.