The OER Research Hub has been investigating the impact of OER, using eleven hypotheses, and a mixed methods approach to establish an evidence base. This paper explores the findings relating to teaching and learning. The findings reveal a set of direct impacts, including an increase in factors relating to student performance, increased reflection on the part of educators, and the use of OER to trial and supplement formal study. There are also indirect impacts, whose benefits will be seen after several iterations. These include the wide scale reporting of adaptation, and the increase in sharing and open practice that results from OER usage.