The Northern states were the epicenter of the wild poliovirus outbreak in Nigeria in 2016. To raise immunization coverage, particularly of polio, the Polio Eradication Initiative (PEI) in Nigeria introduced the use of nongovernmental organizations and volunteer community mobilizers (VCMs) through the CORE Group Polio Project (CGPP). The CGPP has been contributing to Nigeria's polio eradication efforts since 2013. This article explores the contributions of the 2,130 VCMs deployed in 31 participating local government areas in the five implementing CGPP states from 2014 to 2017 to increase awareness, understanding, and acceptance of polio immunization. Data for the study were collected from primary and secondary sources using five collection methods: a survey of VCM supervisors, focus group discussions with VCMs and their supervisors, key in-depth interviews with community stakeholders, case studies of specific best practices of VCMs, and a review of documents and records. A review of the data shows that the VCMs received comprehensive training on the importance of the PEI, routine immunization, Acute Flaccid Paralysis (AFP) surveillance, social mobilization and community engagement, use of behavior change communication tools, and interpersonal communication skills. According to the data collected, the VCMs used the following innovative strategies to ensure high vaccination coverage: house-to-house mobilization, community dialogues, compound meetings, community health camps, and tracking of non-compliant families, missed children, and dropouts. The involvement of VCMs in Nigeria's PEI efforts has been a pivotal contribution to reductions in the number of households rejecting polio immunization, the proportion of families with missed children, the proportion of families that were non-compliant, and the number of polio cases.