["Scandinavian Journal of Psychology, Volume 67, Issue 2, Page 368-382, April 2026. ", "\nABSTRACT\nPolicies and legislation regarding paternity leave influence parental roles and the division of household and childcare responsibilities. However, the impact of paternity leave, particularly how it is shared between parents, on fathers' long‐term involvement in childcare remains insufficiently understood. This study aimed to examine how fathers' absolute and relative paternity leave durations predict their long‐term involvement in childcare. A sample of 985 first‐time fathers was assessed using online surveys when their children were 10 months, 19 months, and 4 years old. Two key predictors were analyzed: absolute leave duration (total weeks) and the relative distribution of leave between fathers and mothers. Multiple regression analyses controlled for relevant confounders. Fathers' absolute and relative leave durations were modestly associated with higher involvement in childcare at 10 months (non‐linear effects). Relative leave was positively associated with involvement at 19 months (linear effect). No significant associations were observed at 4 years. Fathers who shared leave more equally with their partner were also more equally engaged in subsequent childcare early (10 months) and persisting into toddlerhood (19 months), with a larger association observed at 10 months among fathers with shorter leave duration. These findings support theoretical frameworks of “father transformation” and “couples' bargaining” and underscore the potential of non‐transferable paternity leave policies to promote more equitable caregiving roles.\n"]