This study examined the impact of cooperative learning strategies on the performance of senior secondary school students in mathematics in Oyigbo L.G.A, Rivers State. The research was guided by three research questions and three null hypotheses. The study was conducted using a pre-test, post-test quasi-experimental research design. A three-stage simple random sampling method was employed to select a sample of 188 SS II students from a total population of 1,112 public SS II students across the seven public schools in Oyigbo L.G.A, Rivers State. The study utilized three intact classes for the investigation. The data collection instrument, developed by the researchers, was titled "Mathematics Achievement Test" (MAT) and consisted of 20 multiple-choice questions. A test-retest reliability method was employed to determine a reliability coefficient of 0.83. The students in the two EGs were taught the topics of quadratic equations by the formula method and word problems using the Jigsaw cooperative teaching strategy and the TPSS. The students in the control group were taught the same topics using the discussion teaching method. All three groups took a pretest and posttest using the MAT to measure their performance scores. The RQs were addressed using mean and StD, while the null hypotheses were tested using ANCOVA at a 0.05 sig. level. The findings of this study revealed that the use of cooperative learning strategies (Jigsaw and Think-Pair-Share) enhanced the performance of SS II students in mathematics. It was recommended that cooperative learning strategies be adopted as the most effective approach for teaching mathematics in S.S.S in Oyigbo L.G.A and other L.G.As of Rivers State. The study's results indicated that cooperative learning not only facilitated students' understanding of mathematics but also enhanced their performance.