The study investigated the effects of computer-supported learning environment on students’ learning outcomes in Secondary School Chemistry. Specifically, the study determined the effects of Computer-supported Cooperative Instruction (CCI), Computer-supported Individualistic Instruction(CII) and Conventional Teacher Expository Method (CTEM) on students’ performance and retention ability in Chemistry. The study adopted the pre-test, post-test control group quasiexperimental research design. The sample comprised 149 Senior Secondary 1II (SSIII) Chemistry students in their intact classes from three schools purposively selected from three Local Government Areas (LGAs) of Ondo State. Three research instruments were used for collection of data, namely; Computer-Assisted Learning Package on Chemistry (CALPC), Scholastic Ability Test in Chemistry (SATC) and Chemistry Achievement Test (CAT). Data collected were analysed using Analysis of Covariance (ANCOVA). The results of the analysis showed that there was a significant difference in the performance and retention ability of Chemistry students exposed to CCI, CII and CTEM. Both the CCI and CII improved the performance and retention ability of the learners. The CCI was found to be most effective in enhancing better performance and retention ability of the learners. Based on the findings, it was recommended that computersupported cooperative instruction should be encouraged for teaching and learning of Chemistry