Hotels emit large amounts of CO₂ when providing services. Carbon neutrality objectives and the growth of homestays have forced hotel managers to pay more attention to carbon reduction. First, this paper adopted the input–output method to calculate hotel CO₂ emissions. It was found that the amount of CO₂ emissions in the hotel industry decreased from the year of 2016 to 2018, and there are structural differences in the CO₂ emissions of the hotel industry in China. Furthermore, this paper adopted the three-stage SBM-DEA model to evaluate hotel CO₂ emission efficiency in 30 provinces in China. The results show that CO₂ emission efficiency increased significantly when environmental factors were eliminated. A close observation of different regions shows that the eastern region has a higher CO₂ emission efficiency than the western and middle regions. The emergence of homestays has led to increased input slacks in the labor and energy consumption of hotels, which has a negative effect on efficiency indirectly. Finally, implications and recommendations for the hotel industry are proposed.