To motivate electronic word-of-mouth (eWOM) on social media (SWOM), companies offer large rewards; however, the existing academic literature on how incentives influence SWOM communication is limited. To further advance this line of research, this study explores the effect of incentives on senders’ positive emotions which, in turn, promote the senders’ SWOM intention. This study also investigates how unequal types of incentive allocations (i.e., positive and negative inequity) moderate the effect of incentives on senders’ positive emotions and examined the moderating effects of emotion regulation (i.e., reappraisal and suppression) on the relationship between senders’ positive emotions and SWOM intention. We designed an online scenario survey and collected 650 valid responses from WeChat users in China. The empirical results show that (1) perceived incentives positively influence senders’ positive emotions which improve the senders’ SWOM intention; (2) positive emotions mediate the path from perceived incentives to SWOM intention; (3) negative inequity weakens the relationship between perceived incentive size and positive emotions, while the moderating effect of positive inequity is not statistically significant; and (4) reappraisal emotion regulation strengthens the effect of positive emotions on SWOM intention, whereas the moderating effect of suppression emotion regulation is not statistically significant.