This note highlights best practices in designing, implementing and evaluating a project involving a mental health and psychosocial support component. It sets out the arguments for investing in mental health and psychosocial support in FCV situations, including the high prevalence of mental health disorders in FCV settings, their consequences (for individual wellbeing, educational achievement, employment, economic growth, and vulnerability to and perpetration of violence), and the cost-effectiveness of investments in mental health. Victims of conflict and violence, including displaced people, are more likely to develop extreme distress, depression, PTSD, somatization disorder and alcohol abuse, due to their displacement, social isolation, poor access to education and employment, and financial hardship. Other groups in FCV situations who have particular mental health needs include: survivors of SGBV, children and adolescents, wounded and disabled people, people affected by pandemics and emergencies, and helpers and service providers. The note provides links to best practices for the delivery of mental health and psychosocial support services in FCV situations, and emphasizes that international guidelines recommend low-intensity and low-cost Mental Health and Psychosocial Support (MPSS) interventions in non-specialized health care and community settings, complemented by referral of severe cases to specialized health facilities. It also summarizes best practices for specific vulnerable groups in FCV settings, as well as technologies to support mental health programs, noting that people affected by conflicts, particularly displaced populations, have a high ownership rate of cell phones. The note summarizes the common challenges faced by TTLs when incorporating MPSS interventions in FCV situations together with lessons learned. The note concludes by providing links to various resources on evaluating MPSS interventions.