The objectives of this study were to find out whether 1) students' achievement in reading comprehension taught by using INSERT strategy was higher than those taught by using SQ3R strategy, 2) Students' achievement in reading comprehension having high curiosity was higher than those having low curiosity, 3) there was an interaction between teaching strategies and curiosity on students' achievement in reading comprehension. Quasi experimental research with factorial design 2 × 2 was used in this study. The total number of sample were 76 persons, with 38 students of each class (experimental and control classes). The first class was treated by using INSERT strategy and the second class was treated by using SQ3R strategy. The students were also divided into two groups based on curiosity, such as high and low curiosity. The data were collected through reading comprehension by using objective test, whereas for aptitude like curiosity, questionaire was used. The data were then analyzed by applying two-way ANOVA at the level of significance at a = 0.05. The data analysis revealed that (1) students' achievement in reading comprehension taught by using INSERT was higher than those taught by using SQ3R, with F[subscript obs] (27.32) > F[subscript tab] (3.98), (2) students' achievement in reading comprehension with high curiosity was higher than those students with low curiosity with F[subscript obs] (6.92) > F[subscript tab] (3.98), (3) there was an interaction between teaching strategies and students' curiosity on students' achievement in reading comprehension with F[subscript obs] (15.43) > F[subscript tab] (3.98). Tukey test was then applied to verify the interaction between each sample comparison.