This study examines the motivational effects of daily positive work events. Drawing on self-determination theory, we investigated the motivational mechanism of two clusters of commonly encountered positive work events—achievement and recognition events—from a within-person perspective. Specifically, we argue that achievement events and recognition events influence subsequent work engagement through satisfying different psychological needs. We tested our model using experience-sampling data from 200 full-time employees over eight workdays. As hypothesised, after controlling for positive affect as an additional mediator, both achievement and recognition events had positive effects on work engagement through psychological needs satisfaction. The results also revealed that achievement and recognition work events had differentiated effects in satisfying different psychological needs. These results shed light on the motivational function of positive work events above and beyond the affective mechanism and explicate the processes through which different types of positive work events relate to work engagement.