This case study examines the second language socialization of migrant-background (MB) students (n = 8) enrolled in a Greater Montréal public primary school, where the language of instruction is French. This examination includes MB students' experiences learning French and learning through French, and the impact of their knowledge of other languages on their academic experiences. Teachers' beliefs, perceptions, and experiences working with MB students were also investigated to outline participants' needs and challenges in this school context. Data collection included classroom observations (approx. 13 hours), observations of students' in-class peer interactions, six teacher interviews, two focal group interviews with students, and two individual interviews with parents. Findings reveal that learners were socialized to be French speakers, but as non-native speakers, they are also socialized as deficient French speakers. Students' other languages were not valued or viewed as a resource, although findings include signs that students secretly used these resources to support their learning.