© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. A growing body of research demonstrates the role that social groups play in protecting health and well-being in the context of adjusting to acquired brain injury (ABI). However, the psychological processes that underpin this relationship are less well understood. The present research extends this work by testing a theoretically derived model about the role of multiple social group belonging in contributing to improved self-regulation and depression symptoms. A cross sectional survey was conducted involving 50 adults with ABI (Mage = 45 years, SD = 12.10; range 22¿67 years) who completed a series of self-report measures indexing social group membership, self-regulation, and depression. Support for the predicted model was found with mediation analysis showing that multiple group belonging predicted lowered depression symptoms, by providing a basis for enhancing self-regulation. The findings suggest that belonging to multiple groups provides individuals with multiple opportunities for social interaction with which to trial and develop self-regulatory skills, which, in turn, has a positive influence on depression.