Objectives To conduct a systematic literature review of selected major provisions of the Affordable Care Act (ACA) pertaining to expanded health insurance coverage. We present and synthesize research findings from the last 5 years regarding both the immediate and long‐term effects of the ACA. We conclude with a summary and offer a research agenda for future studies. Study Design We identified relevant articles from peer‐reviewed scholarly journals by performing a comprehensive search of major electronic databases. We also identified reports in the “gray literature” disseminated by government agencies and other organizations. Principal Findings Overall, research shows that the ACA has substantially decreased the number of uninsured individuals through the dependent coverage provision, Medicaid expansion, health insurance exchanges, availability of subsidies, and other policy changes. Affordability of health insurance continues to be a concern for many people and disparities persist by geography, race/ethnicity, and income. Early evidence also indicates improvements in access to and affordability of health care. All of these changes are certain to ultimately impact state and federal budgets. Conclusions The ACA will either directly or indirectly affect almost all Americans. As new and comprehensive data become available, more rigorous evaluations will provide further insights as to whether the ACA has been successful in achieving its goals.