Email has become a requisite form of business communication. Effective business email writing means accomplishing a task while maintaining rapport. Therefore, teaching business email writing is not only teaching linguistic accuracy but also linguistic functions and genre knowledge. This study examined the effects of genre-based approach (GBA) and data-driven learning (DDL) to facilitate business email writing. The participants were 40 EFL university learners with elementary (n=20) or intermediate (n=20) English proficiency levels from diverse disciplines. They participated in an 8-hour course to write business emails. The data were collected from the pre-test and post-test, and a semi-structured interview. The findings from the t-test analysis revealed that the participants performed better (p = .000) in the genre aspect after the intervention. Semi-structured interviews revealed that the participants were satisfied with the teaching approaches and found DDL useful for their business email writing in the future.