Speaking is considered one of the most important language skills that needs to be developed and mastered by language learners. However, mastering this language skill does not go so easily with the EFL learners.  Many SL and EFL students think of speaking as the most difficult skill to attain since it requires first and foremost a great deal of practice and exposure also. To overcome this problem, teachers should seek a new approach which provides learners with opportunities to improve their speaking skills. One of the highly recommended approaches is task-based language teaching which provides learners with real life contexts to practice speaking English with their classmates. The purpose of the current study is to investigate the effects of using task-based instruction on developing Saudi EFL students' speaking skills. In the second place, it attempts to explore students' perceptions towards the use of task-based learning in the classroom. To this end, 60 Saudi EFL learners in the department of English Language and Translation, Qassim University, Saudi Arabia, participated in the study. To homogenize the participants' level of proficiency, the Quick Placement Test was employed, and the participants with the intermediate level of proficiency were selected. Then, the participants were randomly divided into two groups: thirty students representing the experimental group studied six units practicing English speaking under task-based instruction, while thirty students representing the control group studied the same units following the regular instruction. Research data were gathered through speaking tests (TOEIC), semi-structured interviews and questionnaires. The data from the speaking test were statistically analyzed using mean scores, standard deviation scores, and t-test for dependent samples and paired-sample. The speaking test findings indicated that there were statistically significant differences between the mean scores of the experimental group and that of the control group on the post-test in favor of the experimental group which was exposed to the task-based instruction in the speaking skills. Moreover, a qualitative analysis of the interviews and questionnaire data demonstrated that the majority of the experimental group had positive reactions to the task-based instruction.  They admitted that they liked the TBSA and wanted to use it frequently in learning speaking. The majority of the experimental group also added that their speaking ability has improved after implementing TBLT. The results of the current study can also be useful for teachers and curriculum planners when designing future curricula textbooks.