Reading and reading comprehension are crucial skills, yet many primary school students struggle. To address this, fostering both the skill and will for reading is a central aim in literacy education. Reading motivation is considered a multidimensional construct, including autonomous reading motivation (ARM), driven by personal value and pleasure; controlled reading motivation (CRM), driven by internal or external pressures; and self-efficacy, reflecting expectations for success. One way to stimulate students' reading motivation, particularly ARM, in school is by giving them autonomy, such as for example offering choices between reading materials. The present study used a person-centered multilevel latent profile analysis approach to identify reading motivational profiles and their relationship with student demographics and reading comprehension among grade 4 students. The association between students' profile membership and teachers' autonomy-supportive behavior was furthermore assessed. Four distinct reading motivation profiles were identified. The high-quality motivation profile, characterized by high ARM, high self-efficacy, and low CRM, exhibited the highest reading comprehension scores. Students with high ARM, high CRM, and low self-efficacy showed the lowest reading comprehension scores. In line with our expectations, students in classes with higher levels of perceived autonomy support were less likely to belong to profiles characterized by low and moderate levels of ARM, CRM, and self-efficacy, and more likely to be in the high-quality motivation profile. Overall, these findings highlight the complexity of reading motivation and its dynamic relation with reading comprehension. Implications for researchers and educators are discussed.