Teacher motivation is crucial for teaching quality and student learning. Although it has been proposed that teacher motivation is reciprocally related to teaching behaviors and student outcomes, such relations have rarely been tested. Thus, the question whether teacher motivation precedes teaching behaviors and student outcomes, or vice versa, is unresolved. This study aims to examine reciprocal relations between mathematics teachers' self-efficacy for emotional support and enthusiasm for teaching, theoretically aligned student-reported teaching behaviors (student-reported emotional support and teacher enthusiasm), and students' mathematics enjoyment and achievement. Participants were 959 students and their 50 mathematics teachers who participated in at least two of three measurement occasions between the beginning of Grade 9 and the middle of Grade 10. Multilevel manifest cross-lagged panels were carried out using three waves of student and teacher data. Teacher self-efficacy predicted subsequent student-reported emotional support, whereas teacher enthusiasm positively predicted expressed enthusiasm. Teacher self-efficacy also contributed positively to subsequent student enjoyment. Student-reported emotional support positively predicted subsequent student enjoyment, and students' achievement positively predicted subsequent student-reported emotional support and expressed enthusiasm. Our findings indicate that teacher motivation precedes teaching behaviors and student outcomes, rather than the other way around. •Reciprocal effects of teacher motivation, teaching and student outcomes are focused.•Multilevel cross-lagged analyses based on 959 students and their 50 math teachers.•Teacher motivation predicted support, expressed enthusiasm and student enjoyment.•Student-reported support predicted student enjoyment (but not achievement).•Student achievement predicted student-reported support and expressed enthusiasm.