This article interprets how five left-leaning parties in Sweden and Spain intend to politically socialise their members through the use of educational activities. By applying a framing perspective on interviews with leading party representatives from the five parties, the analysis theoretically illuminates how educational activities can be a tool for mobilisation. While the interviewed party representatives stress that educating their members has several functions for a party, three salient frames about party education are identified in the interview data as follows: education as (1) movement building, (2) training members and leaders and (3) deliberative reflection. Categorising the different ways that in which education is understood shows how different political motives are integrated into parties' education. Hence, the findings emphasise the intermediating role that education plays between a party organisation and its members in left parties.