Co-production is the involvement of citizens in the design and delivery of services. In primary schools, this involves parents working with teachers to improve the educational development of their children. In this contribution, we present the results of a systematic literature review on co-production in primary schools to establish what research has been conducted and to what extent there is evidence on the effectiveness of co-production in this context. After three subsequent steps of literature selection, an initial database of 3121 articles was reduced to 122 articles which were then carefully analysed. Generally, co-production in education tends to be aimed at specific groups, which makes it hard to generalize, but some findings appear more generally applicable. Co-production does appear to improve students' knowledge acquisition. Parent-teacher relationships can be difficult and ambiguous, but teacher training appears to be an effective tool for improving co-production.