Quitlines provide a model for the translation of research findings to public health application. Quitlines are currently in operation in more than half of US states, in Canada, and in multiple countries globally. Overall, when implemented correctly, quitlines have been shown to be efficacious and effective. Multiple quitline models are in use, but there is no evidence on the relative effectiveness of one over the other. Differences have been demonstrated for the efficacy of quitlines for specific applications, with the strongest evidence base for application as a primary intervention or as follow-up for hospitalized patients and particularly for cardiac patients. The evidence base for both reactive and proactive services is reviewed, and future directions to continue to advance the field are discussed.