This study investigated to what degree lesson-to-lesson variability in teachers' goal clarification and process feedback explains variability in secondary students’ motivational correlates. Students (N = 570, 24 classes) completed questionnaires at six occasions. Multilevel regression analyses showed that relations between perceived process feedback and experienced need satisfaction (i.e., competence, autonomy and relatedness) were conditional on perceived goal clarification. No such interaction effects between process feedback and goal clarification were found for need frustration (i.e., experiencing failure, feeling pushed to achieve goals, feeling rejected). In general, when students perceived more process feedback or goal clarification, students experienced more competence, autonomy and relatedness satisfaction. Yet, when perceiving very high levels of process feedback, additional benefits of goal clarification were no longer present (and vice versa). In lessons in which students perceived goals to be less clear, they experienced more need frustration. No associations were found between process feedback and need frustration. •Lesson-to-lesson variability exists in teachers' provision of goals and feedback.•Lesson-to-lesson variability exists in students' motivational experiences.•More goal clarification and process feedback relates to more need satisfaction.•More goal clarification relates to less need frustration.•Goal clarification and process feedback build on each other's positive effect.