["Journal of Organizational Behavior, EarlyView. ", "\nABSTRACT\nIn the present study, we investigate the impact of perceived overqualification on the return‐to‐work process following maternity leave. Based on Person‐Environment (P‐E) fit theory's underutilized carryover mechanism, we hypothesized that returning mothers experiencing perceived overqualification would “carry over” their excess abilities to proactive helping behaviors when they feel socially integrated. In turn, we expected proactive helping behavior to foster successful work adjustment. Using three‐wave data from 359 mothers returning to their previous jobs after maternity leave, we found that perceived overqualification was positively related to proactive helping behavior when social integration was high. Proactive helping behavior, in turn, was related to improved job satisfaction via enhanced work‐related self‐efficacy. We found evidence for a moderated sequential mediation in which perceived overqualification was indirectly related to improved job satisfaction via proactive helping behavior and work‐related self‐efficacy when social integration was high. Our study extends the perceived overqualification and work‐adjustment literature by examining P‐E fit theory's notion of carryover and its relation to work adjustment success after maternity leave. Practically, organizations can use our findings to facilitate mothers' organizational reentry, for example, by supporting the social integration of reentering mothers.\n"]