The present study was conducted to observe the effects of the Play-Based Father-Infant Interaction Programme (PBFIIP) on the interactional behaviour of fathers and infants. The study group was composed of 40 12-month-old infants and their fathers in central Mus, Turkey. For data collection, the 'Personal Information Form', the 'Caregiver-Child Affect, Responsiveness, and Engagement Scale', and the 'Denver Developmental Screening Test were used. The study was conducted as an experimental implementation. The evaluation of the study data involved descriptive statistical methods. For normally distributed quantitative data, the Student t Test was used for comparisons between the two groups and the Dependent Groups t Test was used for in-group comparisons. For variables which were not normally distributed, the Mann Whitney U Test was used for their comparisons and the Wilcoxon Signed Rank Test was used for in-group comparisons. The research findings revealed a significant difference in favour of the experiment group (p<0.05) between the pre-test and post-test average scores on the C-CARES father-child and pair forms. Among the infants in the experiment and control groups, no significant difference was detected between their pre-test total score averages in the personal-social, fine motor, language, and gross motor fields; a significant difference in favour of the experiment group was detected between their post-test average scores in the personal-social, language, and gross motor fields; and no significant difference was detected in the fine motor field (p>0.05).