The study examined the Impact of Cooperative Learning Strategy on Students‟ achievement and retention of Social Studies Concepts in Junior Secondary Schools in Kano State, Nigeria. The study used quasi-experimental research design, 384 JSS II Students were sampled. Government Junior Secondary School, KafinAgur and JSS Racecourse were used as Experimental Group; and the selected Students were taught using Cooperative Learning Strategy, while JSS Ja‟en and Janguza were used as "Control Group" and the Students were taught using Lecture Method, with JSS II Students. The study used Social Studies Achievement Test (SOSSAT), and Test of Retention (TOR) as data collection instrument. The study answered five (5) research questions and tested five (5) null hypotheses. The data analysis tools were t-test Independent Sample, Cumulative Mean and Standard Deviation. The finding of the study revealed that JSS II Students performed better when taught Cooperative Learning Strategy compared to their counterparts taught Lecture Method. Therefore, based on the findings of this research, it is recommended that the Cooperative Learning Strategy is more effective with Students of Social Studies at Junior Secondary School than Lecture Method. The Cooperative Learning Strategy is effective for both Male and Female Students at JSS level and in Urban and Rural Schools. Based on the above the study recommended the use of Cooperative Learning Strategy by Social Studies Teachers in teaching JSS Students in Kano State, Nigeria.