This paper proposes the design of an instructional model, referred to as the universal genre sphere, for teaching academic writing in a manner appropriate to all learners, but developed especially with consideration for the needs of English as additional language students with or without diagnosed learning differences. Despite growing research on, variously, second-language writing, English as an additional language and learning differences, there has been relatively little work that explores approaches to the intersections of these topics. Thus, the proposed universal genre sphere model is founded on the pillars of universal design for learning and the tenets of the genre-based approach, especially the teaching-learning cycle, to create more equitable and inclusive, as well as effective, learning environments. The universal genre sphere balances inclusive design that draws upon students’ interests, while breaking learning into manageable and adjustable segments, thus making academic writing more accessible to a greater number of learners. The combination of universal design for learning and the genre-based approach represents an opportunity to create a shift in second-language writing instruction (and, potentially, in L1 writing instruction) that aligns with the principles of inclusive education by reducing barriers in the classroom and providing students with multiple pathways to participate, which could do much to advance knowledge about more inclusive, equitable and effective writing instruction for all learners.