The objective of this study was to investigate the effects of task-based language instruction (hereafter, TBLI) on students’ English speaking performances in the Ethiopian context. A sequential mixed-method design comprising a quantitative and a qualitative technique was employed by involving 84 students from Shambu Secondary School. Among five sections, the researchers chose two sections using a random selection method. Interview, assessment rubrics, and speaking tests were used to gather the data. The researchers then performed one-way ANCOVA and independent t-tests to analyze the data statistically. Additionally, the researchers used theme analysis approaches to examine data from semi-structured interview. The findings indicated that the treatment group's speaking performance was considerably improved by applying the TBLI approach compared to the comparison group's traditional instruction. The data also showed that the quantitative findings demonstrated that those students' views about speaking acquisition were good when utilizing the TBLI approach. To put it another way, because they were eager to learn how to speak, students who were taught using the TBLI approach responded positively and had a good attitude for the TBLI. From the findings, it was recommended that these results might give insights how to select the speaking teaching methods. Journal of Science, Technology and Arts Research, Vol. 13 No. 4 (2024)