BACKGROUNDS: This study administered the Health Literacy Questionnaire (HLQ) among Korean adults to examine its factor structure, reliability, and validity. METHODS: The HLQ items were translated and culturally adapted to the Korean context. The convenience sampling method was used, and data were collected. The difficulty level, confirmatory factor analysis (CFA) using diagonal weighted least squares (DWLS) estimator in R, discriminant validity, and composite reliability were performed. RESULTS: The easiest scale to obtain a high score was "Scale 4. Social support for health" and the hardest was "Scale 7. Navigating the healthcare system." Nine one-factor models fitted well. The nine-factor structural equation model fitted the data well. All HLQ scales were homogenous, with composite reliability. CONCLUSIONS: The Korean version of the HLQ has a strong construct and high composite reliability when applied to Korean adults.