This study investigated the effectiveness of integrating Student Team Achievement Division (STAD), a structured cooperative learning method, and "WebQuest," an inquiry-based technological model (IBTM) on developing university English as a Foreign Language (EFL) students' advanced-level argumentative writing skills and enhancing instructors' positive perceptions about teaching and learning. The study, which was undertaken over a 12-week academic semester, employed a mixed methods pre-test/post-test control/experimental group design whereby six intact rhetoric classes were randomly assigned to experimental and control conditions. The experimental group participants (N = 54) were enrolled in four classes and received argumentative writing instruction incorporating STADIBTM whereas their control group counterparts (N = 24) were enrolled in two classes and received the same argumentative writing instruction without STADIBTM. Four instructors who were involved with the experimental group received training on the implementation of STADIBTM. Qualitative data collection and analysis were utilized. The argumentative essay pre-tests and post-tests along with pre-treatment and post-treatment surveys were used to collect data. The quantitative results were evaluated using ANCOVA analyses. The findings showed that only the less skilled participants of the experimental and control groups were able to significantly improve their argumentative writing. However, their instructors were able to develop more positive pedagogical perceptions and perceived fewer challenges because of STADIBTM-based instruction. Further recommendations are given.