This study was undertaken to establish the effectiveness of the Online Collaborative Learning (OCL) strategy in enhancing students’ achievement in Physical Science. A one-group pretest-posttest pre-experimental research design was used involving one intact class. This study conducted for a period of six (6) weeks during the second semester of the 2020-2021 school year at Lucrecia R. Kasilag Senior High School in Congressional District 1 Quezon City. Purposive sampling was applied to select thirty grade 11 Accountancy, Business and Management (ABM) students for this study. It utilized four research instruments. The data gathered were interpreted quantitatively and qualitatively. The study’s findings revealed a significant difference in the students’ Physical Science achievement mean scores before and after their exposure to Online Collaborative Learning (OCL). Hence, it was concluded that Online Collaborative Learning (OCL) as a teaching-learning strategy had improved students’ achievement in Physical Science. Furthermore, the students stated that they preferred and enjoyed working with a partner because it allows them to share their ideas and gain a more in-depth understanding of the topic. Students also mentioned that Google Docs was a convenient and easy-to-use collaboration tool since they could access information simultaneously when working on the task and did not need to switch applications to communicate with their partners. Thus, teachers are encouraged to use Online Collaborative Learning (OCL) strategy when teaching Physical Science since findings show improvements in the students’ achievement. Conducting further studies on Online Collaborative Learning (OCL) on a larger scope is suggested across grade levels and learning areas to establish its effectiveness.