In this study, the effects of using animated concept cartoons on students' conceptual understanding were investigated using a quasi-experimental design with a pretest-posttest control group. The study was carried out with two experimentals and one control group in a secondary school in Demirci district of Manisa province, and a total of 51 students from three classes participated in the study. The lessons in Experimental Group 1 (n=17) were covered using animated concept cartoons while the lessons in Experimental Group 2 (n=17) were covered using concept cartoons. In the Control Group (n = 17), the lessons were carried out using only the activities in the science curriculum. The data were gathered from this study with conceptual understanding test about matter and heat unit. The study results revealed that the adjusted posttest scores of Experimental Group 1 and Experimental Group 2 did not significantly differ from each other regarding the level of conceptual understanding, whereas the scores of both experimental groups were significantly higher than the scores of the control group.