In this longitudinal study of students with concealable chronic health conditions (CCHCs), we applied components of interpersonal disclosure process models to investigate how illness disclosures and perceived partner responsiveness conferred health and social benefits during the COVID-19 pandemic. Students with CCHCs and in relationships completed online surveys at the beginning, middle, and end of the academic year in which they returned to campus amid the COVID-19 pandemic ( nTime1 = 101, nTime2 = 52, nTime3 = 54). Mixed models showed students with greater illness disclosures and perceived partner responsiveness had better physical health, engaged in less health-compromising behaviors, felt less worried and stressed about the COVID-19 pandemic, and experienced lower illness-related stigma, discrimination, and social isolation. Over time, students’ greater illness self-disclosures predicted lower health-compromising behaviors and illness-related discrimination. Notably, perceived partner responsiveness connected greater illness self-disclosures to better health, COVID-related, and social-contextual outcomes. These findings demonstrate the health and social benefits of talking openly about concealable illnesses with partners and, in turn, feeling cared for, validated, and understood amid the COVID-19 pandemic. This study provides new evidence on relational pathways to better social and health outcomes among those with heightened health risks.