The actions we produce and observe every day can help us learn new ideas or change the way we think. One type of action – the gestures we produce when we talk – has been shown to support learning when incorporated into instructional contexts. Unlike other forms of action, gestures are not used to physically change the world. Instead, they are movements of the hand that can represent and manipulate ideas. Here we review literature demonstrating the powerful effects that gesture can have on learning, and we discuss findings that explore the mechanisms by which these effects occur. Specifically, we explore whether gesture facilitates learning through its capacity to be integrated with speech, its ability to engage the motor system and its role as a spatial tool. Finally, we discuss implications of these scientific findings for educational practice and policy.