Mental disorders constitute a huge global burden of disease, and there is a large treatment gap, particularly in low-income and middle-income countries. One response to this issue has been the call to scale up mental health services. We assess progress in scaling up such services worldwide using a systematic review of literature and a survey of key national stakeholders in mental health. The large number of programmes identified suggested that successful strategies can be adopted to overcome barriers to scaling up, such as the low priority accorded to mental health, scarcity of human and financial resources, and difficulties in changing poorly organised services. However, there was a lack of well documented examples of services that had been taken to scale that could guide how to replicate successful scaling up in other settings. Recommendations are made on the basis of available evidence for how to take forward the process of scaling up services globally.