•We used two-level longitudinal structural equation modeling with student data.•We examine relations between math classrooms, motivation and career plans in math.•Boys report higher teacher expectancies, own expectancies/values and math career plans.•Teacher beliefs, class environments and expectancies/values impact math career plans.•Classroom goals functioned differently at student- and class-levels. This longitudinal study examined the effects of students' perceived mathematics teachers' beliefs (expectations about students' ability and mathematics prestige), classroom goal orientations (mastery and performance-approach), and own mathematics motivational beliefs (success expectancies and task values) at grade 10 (T1), on girls' and boys' career intentions in mathematical fields at grade 11 (T2). Data were collected from 438 students (213 boys) in 5 metropolitan schools in Sydney and Melbourne, Australia. Multilevel SEM revealed links between teacher beliefs, learning environments, student motivations, and mathematical career intentions; different predictors operated at individual and classroom levels. Girls perceived lower teacher expectations than boys, but higher teacher mathematics prestige beliefs. Teachers' expectations and students' motivations were positively related to students' reported prior (grade 9) mathematics achievement. Teacher expectations promoted student-perceived mathematics classroom mastery-goal orientation (MGO) and performance-approach goal orientation (PGO); teachers' mathematics prestige beliefs also promoted PGO. MGO enhanced students' mathematics value, which in turn predicted, together with PGO, their mathematical career plans. Mathematics career plans were positively predicted by aggregate teacher mathematics prestige beliefs and aggregate classroom MGO.