Earlier research on doctoral education has associated study progress with the student's own capabilities and faculty support. The purpose of this study is to investigate how students' personal commitment and various forms of support, as well as their complementary effects, explain progress in doctoral studies. Data were collected by a questionnaire survey among doctoral students of industrial engineering and management in Finland. The study investigates the effect of: (1) support from supervisor, peers and employer, and (2) students' commitment in terms of setting goals, time and plans. The results show that plan commitment and peer support, as well as goal commitment and supervisor support, together have a positive effect on study progress. In turn, time commitment and peer support, and time commitment and supervisor support, jointly lead to better research progress. (Contains 1 figure and 5 tables.)