The purpose of this study was, therefore, first, to explore users’ perceptions of two mHealth apps, one CBT-based app, Quit Genius (QG), and one non-CBT-based app, National Health Service (NHS) Smokefree (SF), over a variety of critical themes. Second, the study also sought to investigate the perceptions and health behavior with respect to smoking cessation for users of each app. To do so, a qualitative short-term longitudinal study was conducted based on semistructured interviews with users, followed by a thematic analysis, which resulted in several higher themes and subthemes. Descriptive statistics regarding participants’ willingness to continue using each of the apps, as well as perceptions and health behavior in relation to smoking cessation, were also calculated.