Studies which consider science teacher identity continue to be a focus for education researchers, particularly given the persistent challenges to retain specialist science teachers. The proliferation of research in this area, without a unifying theoretical framework, has meant the literature is diverse, methodologies are varied, and coverage is patchy. This review article considers to what extent and in which ways the social identity approach (SIA) might provide a useful lens through which to consider middle and/or high school science teacher identity. In doing so, we synthesise the findings from 79 empirical and theoretical publications on science teacher identity in middle and/or high school settings, published since 2000. This review highlights the important role that shared identity and group membership play in developing and sustaining positive identities. We argue that the SIA provides education researchers with a greater understanding of how and why some middle and/or high school science teachers are able to form positive professional identities, whilst others are not. This understanding of both the importance of group membership in the social construction of identities and the processes through which memberships form could helpfully inform teacher education and professional development programmes.