This paper aims to examine how to promote university students' engagement in learning by means of instructor-initiated EFL writing groups. The research took place in Rwanda and was undertaken as a case study involving 34 second year undergraduate students, divided into 12 small working groups and one instructor. The data were collected by means of open-ended group interviews carried out after each of the 12 groups had finished writing an essay in English. In their responses, students acknowledged having improved their interpersonal and collaborative skills through EFL group writing. Students also indicated that, while discussing and interacting with their group members and with the support from their instructor, they improved their English vocabulary, gained new ideas and perspectives, and learned better about text coherence, which led to the improvement of their EFL writing. However, a small section of students did not appreciate writing together due to continued internal disagreements and member incompatibility. Some strategies are proposed to make group work an effective learning tool in and outside the classroom, particularly in EFL contexts.