This study investigated the efficacy of cooperative learning strategy on senior secondary school students (SSII) achievement in literature in English. Three research questions and three hypotheses guided the study. The researcher employed the pretest – posttest, non-equivalent control group quasi-experimental design. However, intact classes were assigned for the study. The study utilized a two group design comprising a treatment group or experimental group (the cooperative strategy) and the control group which employed the conventional method. The study was carried out in Abakaliki Education Zone of Ebonyi State, Nigeria. The study population consisted of all Senior Secondary II (SSII) in Abakaliki Education Zone, Ebonyi State. The number of students in 2019/2020 Session is put at 12452 (Ministry of Education). The sample for this study comprised 281 (134 male and 147 female) students from streams of Senior Secondary School II students of the Ebonyi State University Staff Secondary School Abakaliki. The allocation of intact classes to treatment and control groups were carried out through simple random sampling techniques. The instrument for data collection was A 50 item multiple choice Literature in English Achievement test (LEAT) developed by the researcher with a reliability coefficient of 0.91. Descriptive statistics of adjusted mean with its standard deviation was used to answer the research question while analysis of covariance (ANCOVA) was used to test the hypotheses at 0.05 level of significance. Result of the study showed among others that cooperative learning enhanced significantly the achievement of students more than the conventional method. It was recommended that cooperative learning be adopted for use by literature in English teachers during teaching-learning process because of its proved efficacy in enhancing students achievement in the subject