Early father engagement is associated with numerous positive child outcomes including cognitive development, emotional regulation, and fewer problem behaviors. Various fathering programs attempt to encourage father engagement through teaching fathers about young children?s development and needs. This study examined 181 low-income fathers? child development knowledge (self-perceived and objective) as predictors of father engagement (verbal stimulation, caregiving, and physical play) with infants. Additionally, parenting self-efficacy (PSE) was examined as a mediator. Results revealed that fathers? self-perceived child development knowledge positively predicted engagement with infants (verbal stimulation and caregiving), but objective knowledge did not. PSE did not mediate the relationship between self-perceived knowledge and father engagement. These findings yield important implications for fathering research and interventions, suggesting that it may be particularly beneficial to increase fathers? confidence in their ability to understand and meet their child?s needs rather than exclusively focusing on improving fathers? knowledge of child development.