The aim of this study was to explore the relationship between paternal attitudes, father-child activities, socioeconomic and sociodemographic factors, and the early child productive vocabulary. We also wanted to study if paternal factors affected boys' and girls' language acquisition differently. Our data consisted of 722 fathers and their children, who took part in the large Finnish cohort study titled Steps to the Healthy Development and Well-being of Children (the STEPS study). Child productive vocabulary was assessed at 24 months using the Finnish version of the McArthur-Bates Communicative Development Inventories Toddler-form (CDI-T). Regression analyses revealed that father-child activities and father's social class were the most significant predictors of language development. Some paternal factors were more strongly connected with the positive language development of girls. Single strongest connection was found between the social class of fathers and the language skills of girls.