This study determined the effects of "Team Pair Solo" (TPS) cooperative learning strategy and students' personality type on achievement and attitude to Chemistry. 175 SS2 Chemistry students from eight schools constituted the sample for the study. Three hypotheses were tested using ANCOVA within a 2x3 factorial setting and a pretest-posttest control group quasi-experimental design. The TPS instruction was significantly (F (1,168) = 16.45; p<.05) more effective (adjusted mean score = 9.23) than the conventional instruction (mean = 7.59) on students' achievement. Extroverts obtained significantly (F (2,168) = 6.59; p<.05) higher adjusted achievement score (mean = 9.77) than the ambiverts (mean = 8.08) and introverts (mean =7.79). Also, the TPS favoured the extroverts than the ambiverts and introverts. It was recommended that Chemistry teachers should adopt the TPS strategy with effective supervision for the maximum benefit of all students irrespective of their personality type.