BackgroundGlobally, there is mounting evidence about the importance of father involvement for improving child and family wellbeing. However, there are limited measurement tools available for assessing father involvement in low-resource settings globally. The objective of this study was to develop and validate a scale for measuring fathers’ engagement in caregiving activities for young children and families in rural Kenya.MethodsWe used baseline data collected in February–March 2023 from a cluster-randomized controlled trial of a parenting intervention aimed at improving early child development in Nyamira and Vihiga counties in Western Kenya. The analytic sample comprised 460 primary caregivers of children under 18 months of age (91.3% mothers) who were in a relationship with a male caregiver of the young child (i.e., father). The primary caregiver reported on the 25-item father involvement scale. We conducted exploratory and confirmatory factor analyses to determine the dimensionality of the measure and estimated latent variable regression models to assess construct and predictive validity in terms of associations with sociodemographic factors, other paternal and maternal psychosocial measures, and early child development outcomes.ResultsThe scale had a four-factor structure representing father involvement in (1) childcare activities, (2) play and affection, (3) household chores, and (4) early learning activities. Each factor showed good internal consistency reliability and evidence of multiple forms of validity. The four factors were associated with child and household sociodemographic characteristics and more positive paternal and maternal psychosocial outcomes. Father involvement across all four domains was associated with higher early child cognitive, language, motor, and socioemotional development scores.ConclusionsOur findings highlight the multidimensional nature of fathers’ caregiving roles in the lives of young children and their families. We establish a valid tool for assessing father involvement in rural Western Kenya that has potential for use in other similar contexts.