The study aimed to investigate cognitive and metacognitive strategies and products of cognitive and metacognitive processes that preservice science teachers engaged in while reading heat-temperature text after being exposed to no reading strategy instruction, explicit reading strategy instruction,and peer tutoring reading strategy instruction. This study differs from other strategy teaching studies in terms of determining the cognitive and metacognitive reading strategies used by individuals after being exposed to different types of reading strategy instruction, which which was specifically designed to improve conceptual understanding. This study employed holistic multiplecase study wherein preservice teachers were assigned to one of the three groups that received no reading strategy instruction (n = 9), explicit reading strategy instruction (n = 10), and peer tutoring (n = 10) based on their scores on Metacognitive Awareness of Reading Strategies Inventory and good communication among them. The content of strategy instruction included various domain-specific reading comprehension strategies used for activating cognitive and metacognitive processes that contribute to improving conceptual understanding and conceptual change. It was found that the diversity and frequency of using cognitive strategies and products of cognitive processes were the highest in the explicit strategy instruction group, and the metacognitive strategies and products of metacognitive processes were more diverse and frequent in reading strategy instruction groups compared to no strategy instruction group. [Paper presented at the National Science and Mathematics Education Congress (13th, Denizli, Turkey).]