Objective To study the impact of parents’ and best friends’ smoking, nicotine dependence, and craving on smoking-specific cognitions, and readiness to quit in adolescents with and without asthma. Methods Structural equation analyses were applied to data from a sample of 1,120 daily smoking adolescents, 83 of whom had asthma. Results Adolescents with asthma felt more ready to quit, and cognitions were more strongly related to readiness to quit among adolescents with asthma than among adolescents without asthma. Moreover, best friends’ smoking seemed more relevant to the cognitions of adolescents with asthma. Nicotine dependence and craving were strongly related to cognitions, and to readiness to quit in both groups. The relation between craving and readiness to quit, however, was stronger among participants with asthma. Conclusions Reduction of nicotine dependence and craving is essential for both groups. Youth with asthma may benefit even more from cognitive-based cessation services than healthy youth. The finding that adolescents with asthma are relatively more ready to quit, and that their cognitions are more easily affected can be turned into advantages in asthma-specific cessation services.