This paper explores how mainstream teachers, in mainland China with experience of inclusive education, perceive individual differences (ID) among students in general education classrooms. The study adopted a qualitative research approach and employed purposeful sampling and semi-structured interviews. It was found that the mainstream teachers tended to conceptualise ID among students in accordance with five categories: perceived student ability; perceived student behaviour and motivation; perceived students' personal attributes; perceived family factors and observed learning outcomes. The mainstream teachers' particular concerns in relation to catering for ID were also revealed and discussed.