Many local communities in Kentucky, a state with one of the highest smoking prevalence rates in the United States, have enacted smoke-free ordinances that prohibit smoking in workplaces and enclosed buildings open to the public. Research has shown that such ordinances are clearly beneficial for public health, but their influence on smoking prevalence in the populations they cover remains unclear. This study explores the effect of local smoke-free ordinances on smoking prevalence in Kentucky. We used a database of smoke-free ordinances maintained by the Kentucky Center for Smoke-Free Policy, Kentucky Behavioral Risk Factor Surveillance System survey data, and US Census data. We estimated the proportion of Kentucky adults living in counties with smoke-free ordinances of varying strength; examined bivariate associations between smoke-free ordinances and smoking prevalence; and fit regression models that adjusted for various county-level demographic, socioeconomic, and geographic factors. Smoking prevalence was approximately 5% lower in counties with smoke-free ordinances, even after adjusting for other relevant factors, including a trend in decreasing prevalence throughout the study region. There was a slight dose-response effect related to the strength of smoke-free ordinances after adjustment for these covariates. Smoke-free ordinances appear to have a modest effect on smoking prevalence across the span of several years. Findings demonstrate that although smoking prevalence fell throughout the state during the study period, counties with smoke-free ordinances experienced a greater decline. Future research should examine the strength of smoke-free ordinances in greater detail to better understand their influence on smoking prevalence.