This article reports on a 7-week classroom intervention in two Grade 3 French immersion schools near Montreal, Quebec, that enroll both English- and French-dominant students. The teaching intervention aimed to bridge the students’ first and second languages through collaborative language learning strategies designed to enhance students’ awareness of their and their partner’s language production and a ‘biliteracy’ project that linked English and French language arts content. Data collection consisted of audiotaped interactions between eight student pairs as they worked on collaborative tasks for the biliteracy project. A qualitative and quantitative analysis examined how the biliteracy project and strategy instruction influenced students’ collaborative interaction and reciprocal learning. All recorded pairs engaged in reciprocal strategy use and extensive on-task collaboration; nevertheless, the quality of their interaction was tempered by their engagement in further interactional moves that supported contributions from their partners.