This thesis explores the effectiveness of task-based instruction (TBI) in improving students’ speaking skills as well as student and teacher perceptions of TBI at Anadolu University School of Foreign Languages. Control and experimental class data were gathered through questionnaires, interviews and oral tests. Oral pre- and post-tests were administered to both classes comprising 45 students total. The teacher’s perceptions of TBI were explored in pre- and post-treatment interviews, and a post-treatment interview was also conducted with a focus group from the experimental class. Questionnaires were distributed to the experimental group after each of 11 treatment tasks. Data from the oral pre- and post-tests and questionnaires were analyzed quantitatively while data from the teacher interviews and the focus group discussion were analyzed qualitatively. T-tests were run to compare the improvement between groups and to analyze improvement within groups. The T-tests revealed no significant differences in any of the comparisons. The study demonstrated, however that students’ general perceptions of taskbased instruction were positive, and the interview with the study teacher also yielded a positive result. The questionnaire results demonstrated that students had neutral or partially positive reactions to the treatment tasks but found these helpful in developing their oral skills. Findings of this study may inspire teachers teaching speaking to adapt some of the activities in the usual course book according to a more task-based approach, so that students can participate in oral practice of language actively and in turn help them improve their speaking abilities.