<p>The aging population presents a significant challenge, bringing with it the additional burden of informal eldercare. In this study, we explore how this eldercare burden spills over into the workplace, affecting caregivers’ job outcomes. Specifically, we investigate how employees’ eldercare responsibilities undermine their in-role performance, interpersonal citizenship behavior (OCB-I), and creativity through mental and physical exhaustion. Additionally, we also examine how religiosity, as a personal resource, can help mitigate these negative effects. To test our predictions, we conducted two field surveys in several organizations across different sectors. The findings of both studies indicate that employees’ eldercare burden negatively affects their in-role performance, OCB-I, and creativity. Mediation analysis reveals that this detrimental impact is due to increased mental and physical exhaustion. However, strong religiosity beliefs can mitigate the negative effects of eldercare burden on mental and physical exhaustion. Finally, the results also confirm a moderated mediation effect: religiosity buffers the indirect negative impact of eldercare burden on work outcomes. These findings are discussed considering their implications for theory and practice.</p>