This study investigated the effect of two types of flipped classroom on the Iranian upperintermediate EFL learners' appropriate use of refusals, apologies and requests. The participants of the study included 60 upper-intermediate EFL learners from a language institute in Tehran, Iran. The participants were selected based on convenience sampling in the form of three intact classes. Then, the three classes were randomly assigned to three groups namely, traditional flipping group, debate-oriented flipping group and non-flipping group. The three groups were exposed to 14 treatment sessions. Speech act instruction was offered to the flipping groups through explicit flipped instruction and to the non-flipping group through explicit non-flipped instruction. Moreover, a Multiple Choice Discourse Completion Test (WDCT) was administered to the participants to measure their speech act production ability at the pre-treatment and posttreatment, phases of the study. The results revealed that both types of flipped instruction had a significantly positive effect on the EFL learners' use of the speech acts (F=10.622, p<.0.05; F=19.358, p<.0.05; F=18.785, p<.0.05). Accordingly, EFL teachers are recommended to use flipping methods in an attempt to enhance EFL learners' appropriate use of speech acts.