The primary objective of this proposed three-year (January 01, 2016 to December 31, 2018) project is to assess whether a program of widely accessed mobile phone-based text message interventions ('Happy Quit') will be effective at helping people in China who smoke, to quit. Based on the efficacy of previous studies in smoking cessation, it is hypothesized that 'Happy Quit' will be an effective, feasible and affordable smoking cessation program in China.