The COVID-19 pandemic unmasked striking health disparities within the US healthcare system and significantly impacted vulnerable populations. While much attention on vulnerability has been directed toward older individuals with underlying medical conditions, key populations-including the uninsured, racial and ethnic minorities, and pregnant individuals-were considerably affected and require intervention. This review examines the barriers these populations encountered and outlines how clinicians can engage at the provider, practice, community, and national levels to advance health equity and improve health outcomes for these groups in the post-pandemic era.