Given the importance of digital communication during the COVID-19 pandemic, the need for advancing academic goals through online social capital is more tangibly felt. This study examined the hypothesis that online social capital can improve the students' academic performance, as one of the main academic goals, through the mediation of knowledge sharing in the online environment. Participants in the study were 376 graduate engineering students from five universities in Iran. The findings indicated that the bridging of online social capital had a positive and significant effect on the cognitive and social integrative benefits of online knowledge sharing. Besides, the social integrative benefits and personal integrative benefits of online knowledge sharing influenced academic performance. Finally, the social integrative benefits and personal integrative benefits had a mediating role in the relationship between the bridging of online social capital and academic performance. Implications of the findings are discussed for the students' academic performance and suggestions are provided for future research.