The aim of this research was to find out the effectiveness of Summarizing Strategy to assist students’ reading comprehension. This research used quasi experimental research which was conducted from April until July 2018. The population of the research was all first grade students in SMK-IT Ma’arif NU Karanglewas in academic year 2017/2018. The total population was 110. Purposive sampling technique was used to take the sample of the research. Two classes were selected as the experimental and control group. The instrument of collecting the data was test. The test was done twice, they were pre-test and post-test. The type of the test was multiple choice items, t-test formula was used to analyze the data. Based the computation, t-test result was 4.47 and t-table was 1.788 at the significant level 0.05 with the degree of freedom 52. It showed that t-test result was higher than t-table (4.47 > 1.788). Based on the research result, the hypothesis was accepted. Consequently, it can be concluded that Summarizing Strategy is effective on students’ reading comprehension.