The present study sought to extend prior research in the Chinese context by examining the role of demographic and socioeconomic factors in middle school students' motivation, engagement, academic buoyancy, and adaptability. A total of 2,434 middle school students (aged 11-15 years) in China participated in the study. For demographic factors, gender played the dominant role, with males higher on numerous adaptive motivation and engagement factors and females higher on numerous maladaptive motivation and engagement factors. In terms of student-related SES, it appears that parents' education explains the bulk of variance with higher education levels associated with higher self-efficacy and adaptability. There were no significant interactions between demographics and SES and so the main effects of gender and parents' education are associated with motivation, engagement, and adaptability in relatively independent ways. Taken together, the present study has identified salient socio-demographic factors that play a role in educational processes important to Chinese middle school students' academic development.