Tobacco use and secondhand smoke exposure are leading causes of preventable morbidity and mortality in the United States. Outdoor tobacco smoke exposure conveys many of the same risks as indoor secondhand smoke exposure. Tobacco-free campuses policies are an intervention to promote a positive social norm that encourages smoking cessation, as well as reduces exposure to outdoor tobacco smoke. This dissertation contains a review of the policy implementation literature; findings from a psychometric analysis of the newly developed Tobacco-free Compliance Assessment Tool (TF-CAT) to assess compliance with tobacco-free campus policies; and results of a campus intervention study to promote compliance. The TF-CAT protocol is designed to count cigarette butts, observe smokers, and use GIS mapping to display hot spots. A total of 413 observations in primary and secondary campus locations yielded compliance data on both the academic healthcare and main campuses. Results show support for the concurrent validity of the TF-CAT. Inter-rater reliability of the measure is strong, and the tool is feasible, though time- and resource-intensive. The intervention study tested the effects of an efficacy-based messaging campaign on the number of cigarette butts observed on campus. After distributing 6,000 message cards in high-traffic areas over three days, there were fewer cigarette butts per day per site post-intervention compared to pre-intervention (n = 312 observations; median = 4.7 vs. 1.9; U=2239, p=.004). It is crucial for tobacco control advocates to ensure implementation effectiveness of tobacco-free policies. Future research needs to refine methods to measure policy implementation effectiveness. In addition, interventions need to be developed and tested to promote policy implementation effectiveness.