The aim of this study was to systematically consolidate evidence on perspectives and thoughts of women living with HIV regarding the peer support they have encountered during pregnancy and after childbirth. Mixed studies systematic review. PubMed, EMBASE, Cochrane, PsycINFO, CINAHL, Scopus and ProQuest were sourced from 1981 to January 2022. A convergent qualitative synthesis approach was used to analyse the data. Quality appraisal was performed using the Mixed Methods Appraisal Tool. A total of 12 studies were included, involving 1596 pregnant women and 1856 new mothers living with HIV. An overarching theme, 'From One Mother to Another: The Supportive Journey of Pregnant Women and New Mothers Living with HIV', and two themes were identified: (1) Emotional support buddies and extended networks and (2) Link bridge to healthcare support and self-empowerment. Peer support played an indispensable role in the lives of women living with HIV and served as a complementary support system to professional and family support. What problem did the study address? Pregnant women and new mothers living with HIV face preconceived stigma and discrimination. What were the main findings? Peer support was perceived to be beneficial in enhancing emotional support among women living with HIV and was well-accepted by them. Where and on whom will the research have an impact? Healthcare providers and community social workers could develop or enhance peer support educational programmes tailored to pregnant women and new mothers living with HIV. Policymakers and administrators can leverage public awareness, advocacy and political will to formulate and implement policies and campaigns aimed at fostering awareness and receptivity towards peer support interventions. Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA). No patient or public contribution.