Introduction Mental health units in Australia and internationally are increasingly implementing smoke-free policies. Due to the high prevalence of smoking among clinical populations, this has become an important research area. Purpose of study This study explored the attitudes of mental health professionals toward smoke-free policies in mental health units within Australia. Method Using an online survey design, 98 Australian mental health professionals participated in the study. Results Results indicated that only 25.5% agreed with a total smoking ban. Although supporting smoke-free initiatives within the wider community, participants commonly held attitudes that were unsupportive of smoking bans, and indicated beliefs inconsistent with a smoke-free policy for clinical populations. Discussion Results suggest the need for appropriate staff education and training regarding smoking behaviours and risks, and smoking cessation treatments for clinical populations if smoke-free policies are to be successfully implemented. Implications for practice Findings suggest important implications for holistic mental health care, staff education and training, as well as policy, planning and development, particularly in relation to this treatment group, who are likely to have entered a psychiatric unit in crisis.