Readiness to quit has been found to predict smoking-cessation outcomes in a general population. However, little is known about the relationship between the readiness to quit and smoking-reduction outcomes in patients with schizophrenia treated with pharmacological adjuvants. The aim of this study was to examine the association between readiness to quit and smoking-reduction outcomes in patients with schizophrenia. A total of 308 subjects using nicotine replacement therapy (NRT) (N = 242) or bupropion (N = 66) participated in an 8-week smoking-reduction programme. Participants were categorised into precontemplators (N = 127), contemplators (N = 76) and preparators (N = 105) to quit smoking based on the transtheoretical model. There was a significant difference in change in number of cigarettes (NOC) (p = 0.007) and Fagerstrom test for nicotine dependence (FTND) score (nicotine dependence level) (p = 0.029) across the stages of change. A linear regression model revealed trend of increasing reduction in NOC and FTND scores in different stages of change (NOC: B = -1.22, t = -2.81, p = 0.005; FTND: B = -0.43, t = -2.57, p = 0.011). However, the 7-day point prevalence of abstinence was 5.5% (18/308), but there was no significant association between stage of change and smoking cessation (p = 0.26), possibly due to a very small sample size of successful quitters. In summary, among a cohort of institutionalised chronic schizophrenia patients receiving 8-week NRT or bupropion, stage of change can predict smoking reduction and may serve as a useful indicator for patients' preparedness before a trial of smoking reduction.