Depression, together with suicide is an important contributor to the burden of disease in Thailand. Until recently, depression has been significantly under-recognized in the country. The lack of response to this health challenge has been compounded by a low level of access to standard care, constraints on mental health personnel and inadequate dissemination of knowledge in caring for people with these disorders. In the past decade, significant work has been undertaken to establish a new evidence-based surveillance and care system for depression and suicide in Thailand that operates at all levels of health-care provision nationwide. The main components of the integrated system are: (i) community-level screening for depression in at-risk groups, using a two-question tool; (ii) assessment of the severity of depression using a nine-question scale; (iii) diagnosis and treatment by general practitioners; (iv) psychosocial care provided by psychiatric nurses; (v) continuous care for relapse and suicide prevention; and (vi) promotion of mental well-being and prevention of depression in at-risk populations. Factors such as appropriate financial mechanisms, capacity-building programmes for health-care workers, and robust treatment guidelines have contributed to the success and sustainability of this comprehensive surveillance and care system. By 2016, more than 14 million people at risk had been screened for depression and received mental health education; more than 1.7 million people with depression had received psychosocial interventions; 0.7 million diagnosed patients had received antidepressants; and 0.8 million were being followed up for relapse and suicide prevention. The application of this surveillance and care system has led to an enormous increase in the accessibility of standard care for people with depressive disorders, from 5.1% of those with depressive disorders in 2009 to 48.5% in 2016.