French immersion (FI) programs have continued to grow in popularity across Canada and around the world ( García et al., 2017 ; Johnson & Swain, 1997 ). With its unique content-based language pedagogy, teachers use the target language to teach most subjects of the school curriculum ( Cammarata & Tedick, 2012 ). Research has found that FI students’ language production skills (including writing) are not as strong as their comprehension skills ( Erdos, et al., 2014 ). Questions remain about how to support students’ L2 writing across the FI curriculum. Grounded in a theoretical understanding that recognizes language as a critical tool for the development of complex concepts ( Wertsch & Tulviste, 1994 ), we set out to explore how immersion teachers can better support students’ L2 writing development across the French immersion curriculum and which pedagogies show promise in doing so. Specifically, we examined how elementary immersion teachers can capitalize on the communication opportunities offered in content courses to further strengthen writing instruction. To do so, we analyzed different types of writing tasks designed to bring together language and writing outcomes. The study was developed using Action Research cycles of planning, acting, observing, and reflecting (Kemmis & McTaggant, 2000). Through qualitative data analysis of writing tasks and samples of students’ writing, we identified various types of “writing across the curriculum” tasks that support the learning of language, literacy, and content. We then created an instructional framework highlighting pedagogical shifts and pathways that teachers can use to weave writing instruction across the French immersion curriculum. This framework allows for newly learned language and writing skills to be transferred and reinvested into writing tasks in content courses and enables teachers to develop reciprocity between “learning to write” and “writing to learn.”