This study investigates the relationship between pre-university students’ conceptions of learning with their academic achievement. The sample consisted of 309 students (165 males and 144 females) in Tehran city. Among them, 104 individuals were in Mathematics, 110 in Experimental Science, and 95 in Literature (Humanities). The participants were selected through multistage cluster sampling. To assess their conceptions of learning, Purdie and Hattie’s (2002) questionnaire was used, and to measure their academic achievement, the total mean of high school diploma was considered. The results showed a significant relationship between students’ conceptions of learning and their academic achievement. There is also a meaningful relationship between students’ number of conceptions of learning and their academic achievement.