This study investigated the effects of the flipped learning model (FLM) on first-year university students’ grammatical achievement, perceptions of the model, and learning engagement at Bahir Dar University, Ethiopia. The participants were drawn from first-year Natural Science students enrolled in the "Communicative English Language Skills I" course, with a total of 32 sections available. Using convenience sampling, two sections were selected and randomly assigned to the control and experimental groups. The group's outcomes were compared using a quasi-experimental design because random assignment was not feasible. A mixed-methods approach was then used to triangulate findings and provide a comprehensive explanation for the quantitative results through qualitative insights. Over six weeks, the experimental group received instruction via the Flipped Learning Model, which combined pre-class video lectures with in-class active learning, while the control group was taught using conventional methods (lectures followed by discussion-based group work). Data were collected through pre- and post tests (Cronbach’s α = 0.85 and 0.84, respectively), a Learning Experience Questionnaire (LEQ; α = 0.81), and University Student Engagement Inventory (USEI; α = 0.84). Classroom observation was also carried out. The data analyses included descriptive statistics, t-tests, MANOVA, ANOVA, and thematic analysis. Results revealed statistically significant improvements in grammar achievement among the experimental group. Students also reported generally favorable perceptions of the FLM, particularly appreciating the adaptability of instructional videos. However, some expressed reservations about the effectiveness of in-class activities. No direct correlation was found between grammar achievement and students’ perceptions. The MANOVA analyses through its Multivariate tests and tests of Between Subjects Effects, revealed that the FLM significantly enhanced emotional and cognitive engagement, fostering excitement, enjoyment, and critical thinking, but no significant improvement was observed in behavioral engagement. The findings suggest that the FLM positively influences grammar learning and promotes deeper emotional and cognitive engagement, highlighting its potential for creating an interactive learning environment. The study underscores the importance of structured pre-class preparation in enhancing the students’ grammar achievement and their learning. Finally, a discussion of the findings, conclusions, implications for teaching practices, recommendations, and future research areas are presented in light of the findings