In response to contemporary challenges in mathematics education, such as student disengagement (Shabab, 2024; Skilling and al., 2021) and equity issues (Cai et al., 2020), this research builds on a pilot project, "Parent partenaire en enseignement" (2022-2023). Conducted in a Franco-Ontarian school, the project involved 80 students, 8 parents, and school administrators in co-teaching experiences to improve student achievement and social-emotional learning (SEL) skills, as emphasized in Ontario’s revised mathematics curriculum (OME, 2020). The co-teaching model, structured around the phases of co-planning, co-instruction, and co-evaluation (Harent, 2023), explored the potential of parental involvement in mathematics education. This research addresses three primary questions: How can structured parent-teacher co-teaching in mathematics enhance student engagement and academic achievement, particularly for diverse and marginalized students? What are the key components of an effective co-teaching framework that integrates parents into formal mathematics instruction? How does co-teaching influence the development of students' SEL skills, and how does it impact equity in mathematics education? Preliminary findings from the pilot suggest that parent involvement positively affects student motivation and mathematical performance, particularly for students with special needs (Sileo and Van Garderen, 2009). Additionally, co-teaching facilitated the development of SEL skills (Claus et al., 2022). This approach also strengthened school-family collaboration (Deslandes, 2019), creating a more inclusive and supportive learning environment. The ongoing research seeks to refine and validate this framework through an iterative research-development methodology (Bergeron & Rousseau, 2021), addressing challenges related to inclusion, well-being, and teacher professional development (Gardesten, 2023).