The COVID-19 pandemic has had negative consequences on the mental health of the population, which has been documented. Marginalised groups that are at risk of poor mental health overall have been particularly impacted. The purpose of this review is to describe the mental health impact of the COVID-19 pandemic on marginalised group (i.e. persons who are socio-economically disadvantaged, migrants and members of ethno-racial minorities, experience homelessness) and identified interventions which could be well-suited to prevent and address mental health difficulties. We conducted a literature review of systematic reviews on mental health difficulties since the beginning of the COVID-19 epidemic and appropriate interventions among marginalised groups published from January 1, 2020 to May 2, 2022, using Google Scholar and PubMed (MEDLINE). Among 792 studies on mental health difficulties among members of marginalised groups identified by keywords, 17 studies met our eligibility criteria. Twelve systematic reviews examining mental health difficulties in one or several marginalised groups during the COVID-19 pandemic and five systematic reviews on interventions that can mitigate the mental health impact of the COVID-19 pandemic were retained in our literature review. The mental health of marginalised groups was severely affected during the COVID-19 pandemic. Most frequently reported mental health difficulties included symptoms of anxiety and depression. Additionally, there are interventions that appear effective and well-suited for marginalised populations, which should be disseminated on a large scale to mitigate the psychiatric burden in these groups and at the population level.