The present study aimed to examine the effect of concept mapping strategy on problem-solving ability in Mathematics among secondary school students. A true experimental pre-test–post-test control group design was adopted for the study. The sample consisted of 60 students, selected through random sampling and divided into experimental (n = 30) and control (n = 30) groups. A researcher-developed Problem-Solving Ability Test was used for data collection, and its reliability was established prior to administration. The experimental group was taught using concept mapping strategy, while the control group received traditional lecture-based instruction for a period of four weeks. Data were analyzed using mean, standard deviation, and independent samples t-test. The results revealed no significant difference between the groups in the pre-test, indicating initial equivalence. However, a significant difference was observed in the post-test scores (t = 6.15, p < 0.01), with the experimental group showing higher performance. The findings indicate that concept mapping strategy has a positive and significant effect on students’ problem-solving ability in Mathematics. The study suggests that incorporating visual and structured learning strategies can enhance conceptual understanding and improve academic outcomes. Therefore, concept mapping is recommended as an effective instructional approach in Mathematics classrooms.