Heatwaves associated with climate change threaten biodiversity by disrupting behaviours like parental care. While parental care may buffer populations from adverse environments, studies show mixed results, possibly due to heat stress affecting different care components. We investigated how heat stress impacts parental care and offspring performance in the burying beetle Nicrophorus nepalensis under control and heat stress conditions. We examined pre-hatching and post-hatching care by reciprocally exchanging carcasses across both conditions. Heatwaves affecting only one care period did not alter reproduction, but when both were stressed, reproductive success declined. Females exhibited higher energy expenditure during provisioning, evidenced by greater body mass loss. Notably, heat stress had long-lasting effects on offspring via carcass preparation, resulting in smaller adult size and higher mortality. These results highlight the complexity of environmental stressors on parental care, suggesting that different care components may evolve independently, while underscoring the limits of care under prolonged heat stress.