BACKGROUND: Antenatal care (ANC) and postnatal care (PNC) are critical opportunities for women, babies and parents/families to receive quality care and support from health services. Community-based interventions may improve the accessibility, availability, and acceptance of this vital care. For example, community mobilization strategies have been used to involve and collaborate with women, families and communities to improve maternal and newborn health. OBJECTIVE: To synthesize existing reviews of evidence on community mobilization strategies that strengthen support for appropriate and timely use of ANC and PNC. METHODS: Six databases (MEDLINE, Embase, CINAHL, PsychINFO, Cochrane Library, PROSPERO) were searched for published reviews that describe community mobilization related strategies for ANC and/or PNC. Reviews were eligible for inclusion if they described any initiatives or strategies targeting the promotion of ANC and/or PNC uptake that included an element of community mobilization in a low- or middle-income country (LMIC), published after 2000. Included reviews were critically appraised according to the Joanna Briggs Institute (JBI) Checklist for Systematic Reviews and Evidence Syntheses. This review of reviews was conducted following JBI guidelines for undertaking and reporting umbrella reviews. RESULTS: In total 23 papers, representing 22 reviews were included. While all 22 reviews contained some description of community mobilization and ANC/PNC, 13 presented more in-depth details on the community mobilization processes and relevant outcomes. Seventeen reviews focused on ANC, four considered both ANC and PNC, and only one focused on PNC. Overall, 16 reviews reported at least one positive association between community mobilization activities and ANC/PNC uptake, while five reviews presented primary studies with no statistically significant change in ANC uptake and one included a primary study with a decrease in use of antenatal facilities. The community mobilization activities described by the reviews ranged from informative, passive communication to more active, participatory approaches that included engaging individuals or consulting local leaders and community members to develop priorities and action plans. CONCLUSIONS: While there is considerable momentum around incorporating community mobilization activities in maternal and newborn health programs, such as improving community support for the uptake of ANC and PNC, there is limited evidence on the processes used. Furthermore, the spectrum of terminology and variation in definitions should be harmonized to guide the implementation and evaluation efforts.