Background <p>Housing precarity (HP) is a fundamental determinant of well-being and health among older adults.</p> Objective <p>We explored the association between housing precarity and cognitive function among older adults in South Korea.</p> Design <p>Population-based, cross-sectional survey.</p> Participants <p>A nationwide community-dwelling sample of 9796 adults aged ≥ 65&#xa0;years was analyzed.</p> Main Measures <p>Based on the theoretical framework established in the existing literature, HP was assessed across five dimensions: housing affordability, housing tenure, housing satisfaction, neighborhood quality, and community cohesion. The overall HP level was scored on a scale ranging from 0 to 10 and categorized into four levels: lowest, low, high, and highest. Cognitive function was assessed using the Korean version of the Mini-Mental State Examination, 2nd edition (K-MMSE~2), and <i>z</i>-scores were calculated. A higher K-MMSE~2 score indicated better cognitive functioning. Linear regression analysis was performed to determine the association between HP and cognitive function. Beta coefficients (<i>β</i>) and 95% confidence intervals (CI) were estimated.</p> Key Results <p>The mean age of the sample was 73.9&#xa0;years, with a mean MMSE score of 24.6. Compared to participants with the lowest HP levels, those with the high or highest HP levels had lower MMSE <i>z</i>-scores (<i>β</i> [95% CI] −0.21 [−0.27, −0.15] for high HP; and <i>β</i> [95% CI] −0.29 [−0.35, −0.22] for the highest HP levels). Regarding individual indicators, insecure tenure (not owning a home), housing dissatisfaction, poor neighborhood quality, and low community cohesion were negatively associated with cognitive function.</p> Conclusions <p>Among older adults, high HP levels were associated with poor cognitive function.</p>