The importance of constructivist approach to teaching and learning science is growing significantly. Much of the efforts have been put to develop pedagogies that take into account constructivist views to improve students' learning outcomes. In this regard, concept cartoon is widely recognized as an innovative strategy rooted in constructivism; however, its efficacy in enhancing conceptual understanding in science needs to be investigated in the Pakistani science classrooms. Thus, this study focused on exploring the efficacy of concept cartoons in enhancing students' conceptual understanding in selected science concepts on Science Achievement Test for Heat (SAT-H). For this study, quasi-experimental design (pre-and post-test control group) was used as a research methodology. A total of 65 students from grade VII participated in the study including comparison group (n=35) and intervention group (n=30). The Science Achievement Test for Heat (SAT-H) was developed and validated which was administered to both groups as pre-test (before intervention) and post-test (after intervention). During intervention, intervention group (lG) was taught with concept cartoons and comparison group (CO) was taught with standard teaching practices. The two groups were compared on overall performance on SAT-H, performance on SAT-H content domains (i.e. heat and temperature, methods of heat transfer) and performance on SAT-H cognitive domains (i.e. knowledge, application and reasoning) in both pre-test and post-test. Results of the study revealed that on pre-test, both groups were evenly matched on their overall performance (p>0.05). Similarly, no differences were found between two groups in all content domains (p>0.05). However, among three cognitive domains, performance of the two groups was found to be different on two cognitive domains favoring 10 for application (p<0.05) and CO for knowledge (p<0.05). Conversely, on post-test, both groups showed improvement, however, IG performed considerably better than CG with significant difference (p