Increasingly, teacher learning groups (TLGs) are being deployed as a way to realise high-quality educational designs. There is a need for monitoring and for insights into the development of TLGs. Therefore, in the present study, the 'Dimensions of Social Learning Questionnaire' (DSL-Q) is developed that can be used to map the social configuration of TLGs. This article describes the validation of the questionnaire for student teachers, teacher educators and in-service teachers (n = 488) by means of successive exploratory and confirmatory factor analysis, resulting in an instrument with good psychometric properties. The final version of the questionnaire contains 13 items, divided into three factors: practice integration, long-term orientation and goals, and shared identity and equal relationships. The instrument is suitable for quantitative research to gain more insights into the conditional and the outcome variables of social learning. Future research can incorporate theoretical dimensions regarding the value of the social learning process and its outcomes as well as insights concerning socially shared regulation of learning.