This study investigates cooperative learning strategy and students’ academic achievement in biology. This study was guided by two research questions and two hypotheses using quasi-experimental design. The population of the study was made up of 1255 biology students in 15 public secondary schools in Isi-Uzo L G A. the sample size used was 120 students the instrument used for data collection was biology WAEC past questions drawn from Genetics, Nervous system and Digestive system content areas in biology. Mean and standard deviation were used to answer the research questions while ANCOVA was used to test the hypotheses. Findings revealed that significant difference exist between cooperative learning strategy and traditional learning method in favor of cooperative learning strategy. Based on the findings recommendations were made which includes: adequate attention should be given to the female students since male has been found to perform better than females using cooperative learning. Adequate training should be given to secondary school biology teachers on the use of cooperative learning strategy in teaching biology.