There are several biologic therapies approved in Japan for moderate-to-severe ulcerative colitis (UC) but there are no head-to-head randomized controlled trials (RCTs) or network meta-analysis (NMA) for comparing their efficacy. We aimed to compare the efficacy of biologics approved in Japan (adalimumab, infliximab, golimumab, and vedolizumab) for treating moderate-to-severe UC biologic-naïve patients.