The study investigated the effects of three summary writing strategies; Direct Instruction, Cognitive Strategy and Read-Test Strategy on Senior Secondary School student's achievement in English language summary writing. The study population consists of 12,766 Senior Secondary year two (SS 2) students from Edo South Senatorial District and a sample of 373 students participated in the study. Three research questions which were all hypothesized guided the conduct of the research. A pre-test and post-test quasi experimental design was used for the study. The instrument used for data collection was an Achievement Test in Summary Writing (SATSW) adopted from past West African Examination Council (WAEC) English language Paper 2 question paper. The reliability of the instrument was r.96 with an inter-rater reliability estimate of .89. Both descriptive and inferential statistics such as frequency, mean, standard deviation and ANCOVA were used to analyse the data. The findings revealed significant difference in achievement amongst students taught using the different strategies. The results showed that the experimental group performed better with Direct Instruction Strategy being the most effective for teaching students summary writing. Cognitive Strategy was also found to contribute to students' summary writing than the Read-Test Strategy. Thus, it was recommended that English language teachers should be exposed to training in summary writing strategies like Direct Instructio n and Cognitive Strategy through workshops and seminars with the hope that this would help to enhance students' summary writing skills.