The present study assesses the effects of a lack of social support reciprocity at work on employees' occupational self-efficacy beliefs. We assume that the self-efficacy effects of received support and support reciprocity depend on the specific work context (e.g., phase in the process of organizational socialization). 297 women who returned to work after maternity leave participated at three measurement points (five weeks, eleven weeks, six months after re-entry). We measured self-reported received and provided support as well as occupational self-efficacy beliefs. Women who received a high amount but provided only little support at work (over-benefitting) reported lowered self-efficacy beliefs. As expected, this effect was not found at the beginning of re-entry, but only later, when over-benefitting began to be negatively related to recipients' self-efficacy beliefs. (Contains 3 tables and 3 figures.)