In September 2015, just before the third open enrollment period of the Affordable Care Act’s (ACA) Health Insurance Marketplace was about to open, we surveyed Texans ages 18 to 64 to assess their confidence level in understanding the basic terminology about health insurance plans. Our data show that approximately one-quarter of adult Texans lacked confidence in their understanding of some of the most basic health plan terms, including premium and co-payment. Uninsured Texans were significantly more likely to report a lack of confidence in understanding health plan terminology than their insured counterparts. White Texans generally reported greater confidence than Black respondents. Hispanic respondents reported the least confidence in their understanding of health plan terminology.