Fear of Missing Out (FoMO) is the apprehension stemming from missing out on social interactions, and it is a salient motive for sport consumption. Sport fans are active and engaged on social media, and they give Continuous Partial Attention (CPA) to other screens, displaying online behaviors such as accessing team social media channels while watching live sports on screens. Confirmatory factor analysis and structural equation modeling were performed to examine the role of FoMO, with mediations of social media involvement and CPA, on fans' online engagement with sports teams' social media. Participants ( N = 328) demonstrated that fans with FoMO have a desire to continuously connect with other fans while watching live sports on screens, which leads to engaging in social media activities related to the sport team. This study provides theoretical and practical implications related to sport fans' social media information-seeking behaviors and for social media managers of sports teams, including the operations of live broadcasts during sports games.