Background: Health insurance access and health literacy are critical components of "enabling resources" to encourage uptake of services. We sought to test whether health literacy boosts health services utilization in the context of expanded access to health insurance stemming from the Affordable Care Act. Method: We used individual-level data from 11 states included in the Behavioral Risk Factor Surveillance System 2016. We conducted a two-stage least squares instrumental variables analysis. We instrumented improved access to health insurance stemming from Affordable Care Act Medicaid expansion. As outcome variables, we examined cost as a barrier to needed care, having a personal doctor and receipt of routine health checkups, flu shots, Pap tests, mammograms, sigmoidoscopy/colonoscopy, and dental visits in the past year. We then tested whether the relation between improved health insurance access and health services utilization was moderated by health literacy. Health literacy was measured by a dichotomized scale comprising three items: difficulties obtaining advice or information about health, difficulties understating information from health professionals, and difficulties understanding written health information. Results: We found that improving health insurance access increased the likelihood of reporting a personal doctor while reducing the likelihood of reporting cost as a barrier to care. We also found an interaction effect between health insurance and health literacy on dental visits. However, there was no significant interaction effect between insurance access and health literacy for preventive services utilization. Conclusion: Health literacy did not explain why people fail to access "preventive" services even when they obtain access to insurance, with the sole possible exception of dental visits among individuals with high literacy.