Despite inconclusive evidence regarding the effectiveness of cognitive conflict, educators still consider it a significant instructional strategy. One of the challenges of current research is to study the conditions under which cognitive conflict is effective. This research examines the notion that cognitive conflict may have dissimilar effects for students of different academic levels. The study compares the effectiveness of teaching the control of variables thinking strategy to students of two academic levels (low vs. high) by two different teaching methods [inducing a cognitive conflict (ICC) vs. direct teaching (DT)]. One hundred twenty-one students who learned in a heterogeneous school were divided into four experimental groups in a 2 x 2 design. Results show no main effect of teaching method but do show a significant interaction effect between level of students and teaching method. The findings show that students with high academic achievements benefited from the ICC teaching method while the DT method hindered their progress. In contrast, students with low academic achievements benefited from the DT method while the ICC teaching method hindered their progress. The interaction effect was preserved in a retention test that took place 6 months after instruction. The findings show that previous inconclusive findings regarding the effectiveness of the ICC method can be explained by its contradictory effects on students of different academic levels.