Reading comprehension means the ability to know the meaning of the information provided in the reading text. This comprehension is influenced by various aspects. This research focused on the use of reading strategy as one of many aspects that affect reading comprehension. The researcher determined to investigate the effectiveness of the 3-2-1 strategy when employed in reading comprehension especially on narrative text. This research aimed at investigating the effect of using 3-2-1 strategy on students' reading comprehension achievement. The design of this research was a quasi-experimental research. The participants were the eighth grade students of junior high school. The result in the form of post-test scores was analysed by using Independence sample t-test in SPSS computing system. Based on the calculation of the data analysis, the significant value was 0.046 which was less than 0.05 (p<0.05). The result indicated that there was a significant difference. Therefore, it can be concluded that the 3-2-1 strategy gave a significant effect on the students' reading comprehension achievement.