Although grammar has been central to L2 research and methodology over the years, the approaches to teaching grammar have long been a controversial topic in teaching English as a foreign language (EFL) even today when we are introduced with innovative methods especially with technology. Considered as an innovative and effective instructional approach, Flipped Learning (FL) might have the potential to transform the instructional design of the traditional teacher-led classes through the integration of technology and active learning strategies. To explore the role of flipped learning in the EFL context, the researchers investigated the impact of flipped learning on students' development of grammar proficiency and their attitudes towards the new instructional model. A total of 37 students (19 subjects in the experimental group, 18 subjects in control group), who learn English as a foreign language at a state university in East Europe, participated in this study. The study employed a quasi-experimental mixed-methods research design using a variety of data collection instruments including pre-and post-tests on grammar proficiency, a questionnaire (Flipped Grammar Class Attitude Questionnaire) and semi-structured interviews. The results showed that learners trained through FL considerably surpassed the non-flipped group in terms of their success in English grammar. Furthermore, FL was found to have notably enhanced the students' involvement, engagement, and performance. The results provide insights into the implementation of FL in the EFL context. Further studies might investigate the efficiency of multimedia materials, including animations or video lectures in the use of flipped instruction.