['To investigate the cross-sectional association between smoking and happiness in Chinese adults in Hong Kong.', 'Telephone surveys were conducted between 2009 and 2012, with 4553 randomly sampled Chinese adults (male 54%, mean age 58.3 years) in Hong Kong.', 'Happiness was measured using the four-item Subjective Happiness Scale (SHS) and single-item Global Happiness Item (GHI). Smoking status was categorized as current smokers (7.7%%), ex-smokers (6.5%, 93% quit for >6 months) and never smokers (85.8%). Linear and ordinal logistic regressions were used to calculate adjusted β-coefficients for SHS and proportional adjusted odds ratios (aOR) for GHI in relation to smoking.', 'Compared with current smokers, ex-smokers enjoyed greater happiness according to both SHS (adjusted β\u2009=\u20090.16, P\u2009<\u20090.05) and GHI (aOR\u2009=\u20091.52, P\u2009<\u20090.05) measurements, but current and never smokers were similar. Among current smokers, the number of cigarettes smoked was not associated with happiness, but the lack of any attempt to quit was associated significantly with greater happiness (adjusted β\u2009=\u20090.31 for SHS, aOR\u2009=\u20091.82 for GHI) compared with smokers who had tried to quit but not succeeded. Smokers not intending to quit in the next 6 months had higher odds of happiness (GHI) than those wanting to quit within 6 months (aOR\u2009=\u20091.86, P\u2009<\u20090.05).'] Are ex-smokers happier than current smokers among Chinese adults in Hong Kong?