his study investigates the impact of flipped classroom instruction on secondary school students' interest, problem-solving skills, and achievement in mathematics. A quasiexperimental pre-test/post-test control group design was employed with 60 students divided equally into flipped and traditional instruction groups with the experimental group experiencing flipped classroom instruction. Data were collected using standardized tests and Likert-scale questionnaires, and analyzed through t-tests and ANCOVA. Results revealed that students engaged in flipped learning demonstrated significantly higher gains in academic achievement, problem-solving skills, and engagement compared to their counterparts receiving traditional instruction. Specifically, students in the flipped learning group showed substantial gains in mathematics scores (mean increase from 65.4 to 78.2; p = 0.006; Cohen’s d = 0.85), problem-solving abilities (pre-test mean 55.2 to post-test 68.3; p = 0.003; Cohen’s d = 0.92), and interest and engagement in mathematics (interest: 63.5 to 80.2; p = 0.004; Cohen’s d = 0.88; engagement: 58.7 to 75.3; p = 0.003; Cohen’s d = 0.91). The findings suggest that flipped classrooms are a promising pedagogical approach to enhance secondary mathematics education by fostering active participation and higher-order thinking skills. The study recommends wider adoption and further research into the long-term effects of flipped learning.