Electronic cigarettes (ECs) acting as a gateway to smoking traditional cigarettes (TCs) is a growing public health concern of EC use among youths. To gather the opinions and perceptions of adolescents and young adults (AYAs) on whether and how EC can act as a gateway to smoking TC among youths. A qualitative method included 42 AYAs. Participants identified a significant risk of EC acting as a gateway to TC use, several factors contributing to this phenomenon such as a facilitated transition to smoking or its perception as a harmless toy. Participants considered an even greater gateway threat regarding very young adolescents. A minority did not identify the gateway risk and some believed that it was nicotine-dependent. This potential gateway effect brought forth several recommendations: health professionals should screen adolescents (even very young ones) for EC use and inform consumers of the potential gateway effect; this possible effect should be acknowledged to end the harmless perception many might have; there is an urge for better preventive and regulatory policies directed at protecting adolescents and children who never smoked and support those who have quit.