Introduction Tobacco quitlines are critical components of comprehensive tobacco control programs. However, use of the US National Tobacco Quitline (1-800-QUIT-NOW) is low. Promoting quitlines on cigarette warning labels may increase call volume and smoking cessation rates but only if smokers are aware of, and receptive to, quitline services. Methods We conducted qualitative interviews with a diverse subset (n = 159) of adolescent (14-17 y) and adult (≥18 y) participants of a larger quantitative survey about graphic cigarette warning labels (N = 1,590). A convenience sample was recruited from schools and community organizations in 6 states. Interviews lasted 30 to 45 minutes and included questions to assess basic knowledge and perceptions of the quitline number printed on the warning labels. Data were analyzed using content analysis. Results Four themes were identified: available services, caller characteristics, quitline service provider characteristics, and logistics. Participants were generally knowledgeable about quitline services, including the provision of telephone-based counseling. However, some adolescents believed that quitlines provide referrals to "rehab." Quitline callers are perceived as highly motivated - even desperate - to quit. Few smokers were interested in calling the quitline, but some indicated that they might call if they were unable to quit independently. It was generally recognized that quitline services are or should be free, confidential, and operated by governmental or nonprofit agencies, possibly using tobacco settlement funds. Conclusion Future marketing efforts should raise awareness of the nature and benefits of quitline services to increase use of these services and, consequently, reduce tobacco use, improve public health, and reduce tobacco-related health disparities.