This paper synthesises the evidence produced by 12 projects funded under Theme 1 on effective teaching. This synthesis is based on the review of available literature produced by the RLO-funded projects across the first call as well as relevant outputs from the Impact Initiative.3 It forms the first of three such syntheses, with the other two focusing on ‘Challenging Contexts’ (Call 2) and ‘Accountability’ (Call 3). These syntheses aim to present common and differentiated findings across the RLO research grants – focusing particularly on what the research tells us regarding how to improve learning outcomes, how these findings are situated within the wider literature on education and improving learning outcomes, and policy lessons and achieving impact emerging from this analysis. The syntheses focus specifically on important cross-cutting themes such as gender and girls’ education, education for children with disabilities, gauging access to education, equity and education systems.