This study aimed to investigate the impact of flipped task-based instruction (TBI) on EFL learners' speaking skill and attitude towards this mode of instruction. Four intact classes consisting of 60 EFL learners were assigned to control and experimental groups. The data were collected by administering two speaking tests and a questionnaire investigating the participants' beliefs about flipped TBI. The scores of the participants on the two speaking tests were statistically analyzed through an ANCOVA. The results showed that flipped TBI has a positive impact on EFL learners' speaking skill. In addition, the analysis conducted on the participants' scores on the attitude questionnaire revealed that the attitudes of the participants in the experimental groups towards flipped TBI changed positively. The findings of this study can be theoretically and practically employed by EFL teachers and applied linguists. Manuscript profile