This study aimed to 1) investigate the effects of online collaborative learning in enhancing the English oral communication ability of EFL lower secondary students, and 2) to explore the opinions of EFL lower secondary students towards the use of online collaborative learning. The participants of this study were thirty 9th grade students studying at a private school in Phra Nakhon Sri Ayutthaya province and were selected based on convenience sampling. The current study employed one group pre-test and post-test design. The research instruments utilized were pre-test, post-test, and semi-structured interviews. The data analysis employed the statistics of paired-sample t-test, mean, standard deviation, and content analysis. The results of this study indicated that the English oral communication ability of the students significantly improved after the implementation of online collaborative learning instruction (p = .01), and most participants had�positive opinions towards online collaborative learning.