<p>Evidence indicates that help-seekers underestimate the likelihood that they will receive help that they request from others. The present three-study investigation identifies a new explanation for this underestimation of helping effect in uncovering its link to reciprocity. Study 1a (<i>N</i> = 197) showed that underestimation of helping depends on reciprocity expectations and no longer occurs once expectations for reciprocity have been satisfied. Study 1b (<i>N</i> = 154) established that reciprocity concerns predict underestimation of helping more strongly than does the previously proposed mechanism of a failure in perspective taking, i.e., it demonstrates that reciprocity, and not either discomfort or gratitude, predict underestimation of helping. It also showed that help-seekers and helpers share an understanding of the normative expectations associated with each other’s roles as givers and reciprocators of help and their implications for discourse. Study 2 (<i>N</i> = 111) replicated underestimation of helping in real-life social support interactions as well as demonstrated that help-seekers differ in their outlooks from helpers on features of reciprocity in which their roles differ. Finally, Study 3 (<i>N</i> = 98) demonstrated that giving and reciprocating help influence cognition on an implicit level by shaping memory for helping events. The investigation contributes to a theoretical understanding of the previously unrecognized role of reciprocity in underestimation of helping, and highlights the importance in future research of giving greater attention to the subtle normative pressures linked to reciprocity that are experienced not only by help-seekers but also by helpers.</p>