To better address the inequities and inequalities brought by the monotonous approach to low-carbon development, it is necessary to actively explore inclusive low-carbon development (ILCD) pathways, and low-carbon policy (LCP) synergy plays a crucial role in ILCD. This paper manually collected LCP data from 30 provinces in China from 2010 to 2019 and conducted a study using text analysis to measure LCP subject synergy, LCP tool synergy, and LCP overall synergy. At the same time, an indicator analysis framework of ILCD was constructed to measure the efficiency of ILCD at the provincial level through the super-efficient SBM model. On this basis, the impact of LCP synergy on regional ILCD is explored to reveal its mechanism of action, and heterogeneity is explored. The results show the following: (1) In general, LCP subject synergy, LCP tool synergy and LCP overall synergy all effectively promote regional ILCD. (2) Both LCP subject synergy and LCP tool synergy are indispensable. Policy synergy can positively affect ILCD only when both policy subjects and policy instruments are highly synergistic, while ILCD is significantly weakened when both policy subjects and policy instruments are lowly synergistic. (3) The stronger the innovation capacity of provinces, the stronger the contribution of LCP synergy to ILCD. (4) In non-resource-based regions, the effect of LCP subject synergy on regional ILCD is more significant, and the effect of LCP tool synergy is not significant, while the opposite is true for resource-based regions. The study plays a certain reference significance for the government to improve LCP synergy and promote regional ILCD.