PurposeAlthough the trajectory of mental disorders can be improved with timely treatment, many people defer treatment-seeking. This study aimed to examine the prevalence and correlates of treatment delays for mental disorders in Singapore, as well as perceived effectiveness of treatment received.MethodsA total of 6126 respondents, aged 18 and above, participated in the Singapore Mental Health Study 2016-a cross-sectional, nationwide study conducted in Singapore from 2016 to 2018. Lifetime treatment contact for mood, anxiety, and alcohol use disorders (AUD) was assessed using the World Mental Health-Composite International Diagnostic Interview (Version 3.0). Multivariable logistic regression was conducted to examine correlates of delayed treatment.ResultsA total of 137 participants had made lifetime treatment contact for a mental disorder. The proportion of respondents who received delayed treatment (i.e., at least one year after onset of disorder) was 60.8% for any disorder, 59.5% for mood disorders, 56.3% for anxiety disorders, and 92.7% for AUD. The median delay was 5 years for mood disorders, one year for anxiety disorders, and 4 years for AUD. Treatment delay was significantly associated with older age, higher educational qualification, lifetime AUD, and earlier age of onset of disorder. 58.4% of respondents with lifetime treatment contact had received treatment that they considered effective.ConclusionThe high prevalence and long durations of treatment delay underscore the need to encourage help-seeking for mental disorders, especially since treatment is generally perceived to be helpful. Our findings also highlight several population groups more susceptible to receiving delayed treatment.