Background: An important pedagogical practice is the provision of structure (Farkas & Grolnick, 2010, "Motiv. Emot.," 34, 266). According to self-determination theory (SDT; Deci & Ryan, 1985, "Intrinsic motivation and self-determination in human behavior," Plenum, New York, NY), structure allows students to develop perceived competence in different school subjects, which in turn facilitates the development of autonomous motivation towards these subjects and limits the development of controlled motivation. Aims: In this study, we test a mediated moderation model that posits that teacher structure has a stronger positive effect on students' autonomous motivation (and a negative effect on controlled motivation) in French class when differentiated instruction is used, and that this moderation effect is mediated by perceived competence. Sample: To test this model, we used a sample of 27 elementary school teachers and 422 students from Quebec, a province of Canada. Methods: Data for teachers and students were collected with self-report measures. The method used was a correlational one with a single measurement time. Results: Results revealed that (1) the effect of teacher structure on students' autonomous motivation was positive only when differentiated instruction strategies were frequently used, and this moderated effect was partially mediated by perceived competence, and (2) teacher structure was negatively associated with students' controlled motivation only when differentiated instruction was provided infrequently, and this moderated effect was not explained by perceived competence. Conclusions: These findings are discussed in the light of the literature on SDT and on differentiated instruction.