Abstract: Agricultural machinery services, as a key substitute production factor for agricultural labor, have drawn considerable attention regarding their impact on rural residents’ participation in off-farm employment. However, systematic research on how these services affect rural residents’ time allocation among farming, off-farm employment, and non-productive activities remains limited. Using nationally representative primary survey data collected in 2019 and 2023 from 2,000 households across 100 villages in 50 townships of 25 counties spanning five provinces, this study systematically analyzes the effects of agricultural machinery services on rural residents’ time allocation and its heterogeneity. The results show that: 1) a 1 percent increase in the utilization of agricultural machinery services is associated with an average annual reduction of 0.61 hours in farming time and an increase of 1.03 hours in off-farm employment time, while non-productive activity time does not change significantly; 2) agricultural machinery services increase household agricultural income and individual off-farm income, with household average hourly agricultural income rising by 0.088 yuan and individual annual off-farm income increasing by 16.34 yuan; 3) agricultural machinery services in the sowing and harvesting stages significantly promote time reallocation by reducing farming time and increasing off-farm employment time; and 4) the effects are more pronounced among vulnerable groups, including females, the elderly, and less-educated individuals in reducing farming time, as well as among low-income groups in increasing off-farm employment time. Based on these findings, it is recommended that governments strengthen support for agricultural machinery services, with a focus on mechanization in sowing and harvesting, to optimize rural residents’ time allocation and promote coordinated improvements in agricultural productivity and inclusive off-farm employment.