This mixed-methods study investigates the effectiveness of flipped classroom instruction in English as a Foreign Language (EFL) contexts. Drawing on both quantitative and qualitative data, the research explores how flipped learning environments influence students' language performance, engagement, and perceptions of learning. The quantitative phase involved a quasi-experimental design with pre- and post-tests administered to two groups: an experimental group receiving flipped instruction and a control group following traditional lecture-based teaching. Results indicated a statistically significant improvement in the experimental group's performance, particularly in listening and speaking skills. The qualitative phase, comprising semi-structured interviews and classroom observations, revealed increased student autonomy, motivation, and active participation in the flipped classrooms. However, challenges such as unequal access to digital resources and varying learner readiness were also identified. The findings suggest that flipped classrooms hold promise for enhancing EFL learning outcomes in Iranian contexts through flipped learning implementation, though their effectiveness depends on thoughtful implementation, including adaptive strategies for technological barriers and learner preparedness, and contextual adaptation specific to resource-constrained EFL environments. Pedagogical implications and directions for future research are discussed.