Since May 2020, ODI and its Vietnamese and Tanzanian country partners have been engaged in a 2.5-year project to address the mental health needs of adolescents in schools, in the community and at the institutional level through the co-creation and implementation of digital and non-digital solutions. As a first phase of this project, carried out a literature review. This paper contributes to the other outputs published in the literature review. This literature review explores the impacts of Covid-19 on mental well-being and the mental health and psychosocial support needs of adolescents in Viet Nam and Tanzania.