The present study examined EFL learners' perceptions of using flipped learning procedure in a grammar class. The participants recruited were 60 Iranian intermediate male EFL learners, randomly assigned to an experimental and a control group. The learners in the control group, having no preparation prior to class, were given direct instruction by using whiteboard with no or little use of interactivities in their grammar lessons. The instruction in the experimental group, however, featured flipped learning through "WhatsApp" and was augmented through in-class face-to-face discussion. Online teaching as the pre-class preparatory activity grounded the learners in the formal instruction of new grammatical concepts. The in-class time was then used by the teacher to induce learner-centered, meaningful interaction intended to render better comprehension and retention of the target grammar. The data collection instruments were College and Universities Classroom Environment Inventory (CUCEI) and a semi-structured interview. The results revealed that the participants receiving flipped learning instruction found it satisfactory, engaging, and effective. The findings add further evidence to the existing literature on flipped learning and have implications for curriculum development and pedagogy enhancement.