The responsible low-carbon behavior of household residents is a crucial factor for the purpose of achieving carbon neutrality in the economy and society. Based on the peer effects theory, this study constructs a fixed-effects model to empirically analyze the existence, heterogeneity, and action mechanism of peer effects in household carbon emission behavior, which uses panel data from the China Household Finance Survey (CHFS). The results indicate that peer effects have a significantly positive impact on residents’ carbon emission behavior, and the results are verified by the robustness test in various ways. Further mechanism tests show that peer effects influence carbon emission behavior through methods including the learning imitation mechanism and competitive imitation mechanism. In addition, we find that peer effects have different impacts on residents’ carbon emission behavior in varying regions, income levels, education levels, and ages groups. This study aims to embed residents’ carbon emission behavior into the strong relationship between surrounding groups, raise consumers low-carbon awareness through publicity, guidance, and group interaction, form a low-carbon atmosphere for the whole society, and contribute to the realization of Sustainable Development Goals.