Considerable progress has been made over recent decades in formulating models of care and implementing mental health and psychosocial support (MHPSS) services for refugees worldwide1. The challenges in providing services to this population are being greatly increased by the COVID-19 crisis. At the same time, the World Health Organization has provided impetus to supporting refugees, including in the MHPSS field, by adopting a Global Action Plan extending over the next four years2. It is timely, therefore, to draw on the lessons of past decades to consider what steps will assist in advancing MHPSS services for refugees around the globe. The principles underpinning all MHPSS activities in this field are well established, including a commitment to human rights, cultural integrity and right to regain autonomy of all refugees. Moreover, communities need to be empowered to participate in, and where possible lead, MHPSS programs, a principle that focuses central attention on capacity building and skills development in all MHPSS activities. Guidelines in place for over a decade also direct attention towards the subpopulations in need of special MHPSS attention, including those with severe and disabling mental disorders, and those with more common forms of traumatic stress, mood and anxiety disorders. Also well documented are the core MHPSS activities, including the provision of generic community mental health services, structured psychotherapy programs, and non-clinical psychosocial programs aimed at promoting self-help and resilience in the community as a whole3. The immediate challenge facing the field, however, revolves around the issue of scarcity of resources, a constraint that requires careful matching of selective components to the most urgent MHPSS needs of each population. The size of the population need underscores this principle. A record 80 million persons currently are displaced, representing one percent of the world’s population. The majority are internally displaced or asylum seekers in countries where MHPSS services are at a low level of development. Pooled epidemiological data indicate that, on average, 30% of these populations experience ongoing symptoms of depression, anxiety and/or post-traumatic stress disorder (PTSD)4, and one in 10 meet criteria for moderate or severe forms of mental disorder5. Even discounting these numbers based on natural remission, the size of the population in need of MHPSS services far exceeds the skills base and material resources available to provide equitable interventions at a global level. Systematic baseline assessments facilitate the process of priority-setting and include consideration of the community’s exposure to persecution, violence and loss; the point in the trajectory of displacement where the population is located; the inherent cultural and social strengths and skills base of each group; the threats, assets and enablers for social and economic recovery in the immediate context; and the availability of external support for MHPSS services. The difficulty is that, in real life situations, many influences dictate the choice of interventions in any setting, including the idiosyncratic preference of donors, lobby groups or implementing agencies. Standardization of assessments, systematic decision-making and transparency in the process would greatly facilitate a more rational allocation of resources in each setting. In the early aftermath of humanitarian crises, persons with mental illness manifesting bizarre or disorganized behaviour are at high risk of abandonment and neglect, falling physically ill, being injured or assaulted, or experiencing abuse and exploitation. Psychiatric diagnosis is only a broad indicator of need, given that individuals with a wide range of problems may reach a point of social crisis in these settings. As a consequence, services need to be prepared to deal with a range of people, including those with psychotic disorders; delirium or dementia; depression and other emotional disorders; medically unexplained somatic complaints; and adjustment disorder associated with self-harm or dangerous behaviours6. In some settings, mental health services are also the only source of intervention for persons with epilepsy, alcohol and substance use disorders, and intellectual disability or developmental disorders. Low-cost mobile emergency teams led by psychiatrists and other mental health professionals, supported by community health teams of workers provided with intensive training and ongoing supervision, can provide psychotropic medications and social and family support in these unstable settings, averting the need for inpatient care except in the extreme instances. In more stable environments, such as refugee camps or urban settings, it may be feasible to introduce more systematic programs of psychological therapies for PTSD, complicated grief reactions, and other common mental disorders such as depression. Models of psychotherapy tend to apply overlapping techniques derived from cognitive behavioural and other evidence-based strategies used in high-income countries, although adapted to the local culture and context7. Some programs are based more explicitly on cultural concepts of mental health and/or psychosocial models that are specific to refugees8. The use of operationalized training and treatment manuals, and the recruitment of indigenous lay or primary health care workers to administer therapies under supervision, add to the logistic feasibility and cost-containment of these programs. Typically, supervision is provided on site and continued via remote, digital communication by expatriate professionals. In general, these interventions have produced positive outcomes in the short term8, but less is known about whether these effects are maintained over time. The capacity to embed these programs securely within routine community services also needs to be demonstrated. However, the early success of these programs represents a milestone in demonstrating the potential for MHPSS services to make a major contribution to the overall humanitarian relief effort. In high-income countries, refugees constitute two distinct populations based on immigration policy: permanent refugees, who receive full access to public mental health and resettlement services, and asylum seekers without permanent residency status, who are subjected to restrictions and, in some cases, held in detention for prolonged periods of time9. In some settings, only permanent refugees have access to MHPSS services provided by specialist refugee agencies. An extensive body of research has demonstrated that the post-migration living difficulties experienced by asylum seekers exert a detrimental effect on their mental health, both in the short and medium term. Moreover, practitioners in the field confront major obstacles and ethical challenges in attempting to provide optimal care to this group. It is vital that the field ensures that the basic principles of human rights and equity are upheld in planning MHPSS services in the future. A global focus requires that careful decisions are made regarding the allocation of resources, in order to provide equitable access to MHPSS services. Given the vagaries of funding, there is a temptation to focus on populations and contexts that most readily garner support by donor countries and other sources. As an exemplar of practice in the humanitarian field, the MHPSS community needs to counteract this tendency, by arguing assertively for the equitable distribution of resources to all those in need. At the front-line, it is vital to uphold the principles of ethical practice, and support colleagues in so doing, especially when working in politically charged situations.