Introduction In 2011, the Mobile County Health Department began a 12-month antismoking educational media campaign to educate citizens on the dangers of secondhand smoke. The campaign overlapped with the Centers for Disease Control and Prevention's 3-month national antismoking Tips from Former Smokers media campaign. We aimed to evaluate the effect of these campaigns on support for smoke-free environments and knowledge of the dangers of secondhand smoke. Methods Cross-sectional precampaign and postcampaign telephone surveys collected data from a random sample of Mobile County adults in the summers of 2011 and 2012. Outcome measures included changes in support for smoke-free environments and knowledge of the dangers of secondhand smoke. The participation rate among the households that were successfully reached was 45% in 2011 and 44% in 2012. Results On the postcampaign survey, 80.9% of respondents reported seeing a television advertisement, 29.9% reported hearing a radio advertisement, and 49.0% reported seeing a billboard. Overall, support for smoke-free bars increased significantly after the intervention (38.1% to 43.8%; P = .01) but not for workplaces or restaur-ants. Self-reported exposure to the media campaign was associated with higher levels of support for smoke-free workplaces, restaurants, and bars. Conclusion Educational mass media campaigns have the potential to increase support for smoke-free protections and may increase knowledge about the dangers of secondhand smoke among certain populations.