Critical thinking (CT) is an essential competence for medical students. Family socioeconomic status (family SES) and general self-efficacy (GSE) play crucial roles in the development of CT. However, the association among family SES, GSE, and CT in Chinese medical students has yet to be fully investigated. To investigate the role of family SES and GSE in the development of CT in Chinese medical students. 1,338 medical students were recruited using multistage stratified cluster sampling from three institutions in China. The Chinese critical thinking disposition inventory (CTDI-CV), General Self-Efficacy Scale (GSES), and a self-made inventory assessing family SES were administered to collect data. The relationship between CT and family SES as well as GSE was evaluated by structural equation modeling. Students of higher family SES obtained higher CTDI-CV and GSES scores. A positive correlation was found between family SES and CT ( = 0.101-0.141, < 0.05 or < 0.01), as well as between family SES and GSE ( = 0.111-0.129, < 0.01). Moreover, GSE was moderately correlated with CT ( = 0.418, < 0.01). The model of partial mediate effect of GSE showed the best fit index with = 29.698, = 9 and = 3.300, NFI = 0.990, IFI = 0.993, TLI = 0.984, CFI = 0.993, RMSEA = 0.041. Family SES has a positive albeit limited influence on GSE and CT in Chinese medical students. GSE mediates the effect of family SES on CT and plays a larger role. Enhancing medical student' GSE maybe an efficacious way to improve medical students' CT.