Oxfam Great Britain has become an experienced and effective advocate of evidence-informed policy change, offering lessons for building effective action. In this article, insights from policy studies with specific case studies of Oxfam campaigns are combined to describe four ways to promote the uptake of research evidence in policy: (1) learn how policymaking works, (2) design evidence to maximise its influence on specific audiences, (3) design and use additional influencing strategies such as insider persuasion or outsider pressure, and adapt the presentation of evidence and influencing strategies to the changing context, and (4) embrace trial and error. The supply of evidence is one important but insufficient part of this story.