Research on the faculty impact on students' academic achievement has been disproportionately confined to the context of countries with developed higher education systems. Few studies have been undertaken in the developing world like Cambodia. This study employed hierarchical linear modeling to examine the relationships between faculty behaviors and the academic achievement of university students in Cambodia, using the data of 923 first-year students from nine universities in Phnom Penh City. Results indicated that faculty behavior, namely their support and feedback to students, was a unique factor that had a strong and positive influence on students' academic achievement. Its effect was the same for all students regardless of their pre-university academic experience and geographical origin and partially moderated by student engagement in time spent on course-related tasks outside the classroom, assigned homework/tasks, class participation, and class preparation. Contrary to existing findings from faculty impact studies, no relation was found for faculty's instructional organization and clarity or classroom practices that challenge students on academic achievement. Practical implications for assessment policies and instructional practices are discussed.