Introduction: Children still die from vaccine-preventable diseases. Nigeria contributes 30% of unimmunized children <5 years globally. This study was conducted in 4 Local Government Areas (LGA) in Niger and Gombe States employing the positive deviance (PD) approach to increase vaccination demand in low child immunization coverage settings. Methodology: The was a quasi-experimental study, conducted between December 2019 and April 2021, comparing pre- and post- intervention vaccination uptake after 5 months of intervention among 400 caregivers of non-fully immunized children (CNFIC). We trained 40 caregivers of fully immunized children (CFIC) as mentors using a participatory learning and action tool. The CNFIC were matched in ratio 10:1 with CFIC and exposed to 8 impact meetings and 10 home-visits using communication materials to increase vaccination knowledge. Paired T-test and adjusted odd ratios from logistic regression models were used to determine change in immunization uptake and factors associated with full immunization for age, respectively. Result: A total of 343 CNFIC were successfully followed up during intervention. The age range of children in the study was 2 to 12 months with the female (178) slightly more than the male (165). The mean vaccine uptake rate increased from 43.7% to 85.9% (T= -29.3, P<0.005) with 55.4% fully vaccinated for age post-intervention. Safer LGA residence, being a housewife caregiver, and younger caregivers <30 years were positive determinants of full vaccination. Conclusion: Adopting the PD approach to low uptake vaccination settings can increase vaccination demand and coverage. This approach can be leveraged in other public health challenges.