Integration of family planning and immunization services provides an opportunity to meet women's need for postpartum family planning and infants' vaccination needs through client-centered care, while reducing financial and opportunity costs for families. The United States Agency for International Development's Maternal and Child Survival Program (MCSP) supported the Liberia Ministry of Health to scale up integrated family planning and immunization services as part of a broader service delivery and health systems recovery program after the Ebola epidemic.We conducted a mixed-methods program evaluation in 22 health facilities in Grand Bassa and Lofa counties. Family planning uptake and immunization dropout rates at project sites were compared to rates at 18 matched health facilities in the same counties. We conducted 34 focus group discussions with community members and 43 key informant interviews with health care providers and managers to explore quality of care and contextual factors affecting provision and use of integrated services including postpartum family planning.From November 2016 to July 2017, 1,066 women accepted referrals from immunization to family planning counseling (10% of all vaccinator-caregiver interactions); the majority of women who were referred (75%) accepted a family planning method the same day. Trends indicated slightly higher family planning uptake in intervention over nonintervention facilities, but differences were not statistically significant. Pentavalent vaccine dropout rates did not increase in intervention compared to nonintervention facilities indicating no negative impact on utilization of immunization services. Clients and providers expressed that the integrated services reduced costs and time for the clients, educated mothers about postpartum family planning, and ensured infants were completing their vaccinations. Providers expressed the need for increased human resources to meet the elevated demand for family planning counseling services and additional focus on community-level social and behavior change activities. Both groups emphasized that social stigma and norms about postpartum sexual abstinence prevented many women from seeking postpartum family planning services.Although scaling up integrated family planning-immunization services may be programmatically feasible and acceptable to clients and providers, the intervention's success and ability to understand and quantify impact are driven by the effect of contextual factors and fidelity to the intervention approach. Contextual factors need to be understood before implementation, measured during implementation, and addressed throughout implementation to maximize the approach's impact on service utilization and health outcomes.