Objectives: To study the effects of a faith-based smoking cessation intervention during Ramadan among Malay male smokers working in public offices. Methods: This was a quasi-experimental study conducted during Ramadan 2015. The intervention was developed based on the constructs within the Theory of Planned Behaviour. The intervention intended to increase the intention and the perceived behaviour control to stop smoking among Muslim smokers during Ramadan. The outcomes measured were changes in the Fagerstrom Test for Nicotine Dependence score and saliva cotinine levels. Data were collected at baseline (5 days before Ramadan), during Ramadan (21st day of Ramadan) and post-Ramadan (21 days after Ramadan). Statistical tests to examine changes within and between groups were carried out and the significance level was set at p