The present study set out to investigate the effect of a newly-developed model of writing instruction in comparison with Swalesian genre approach, and the traditionally-favored product-oriented approach on Academic Writing Motivation of Iranian EFL learners. The devised model was called System-Nested, Genre-Oriented, Structurally-Mediated Model of Writing Instruction. Next, with a quasi-experimental design, three groups of learners received writing instruction via traditionally-favored product-oriented approach (N = 8), Swales’ genre-based approach (N = 8), and the newly-developed model (N = 7). The participants received an academic writing motivation questionnaire prior and subsequent to their treatments as pretest and posttest. The results of ANCOVA revealed that the participants in the newly developed model group outperformed the other two groups on the posttest of writing motivation. Additionally, the learners in the Swalesian genre approach group performed significantly better than those in the product-oriented approach group. Language teachers are encouraged to incorporate the system-nested, genre-oriented, structurally-mediated model of writing instruction or other genre-based models to improve learners’ academic writing motivation.
