This study sheds light on the relationships between workplace stressors and employee innovation by jointly considering mediating processes and boundary conditions. Using the challenge-hindrance model, we combine social exchange and conservation of resources theory to propose that challenge (i.e., role overload) and hindrance (i.e., role ambiguity and role conflict) stressors exert positive and negative indirect effects, respectively, on employee innovation through affective organizational commitment. We further posit that the strength of these relationships depends on the quality of leader-member exchange (LMX). In support of these predictions, a time-lagged study of 134 employees from various Canadian firms found affective commitment to mediate the differential relationships of challenge and hindrance stressors to employee innovation. Moreover, when LMX was high, the positive effects of role overload were enhanced while the negative effects of role ambiguity and role conflict were attenuated. We discuss the implications of these findings for theory and practice.