Since the mid-1990s, the vast majority of fathers in Sweden have used parental leave, albeit for shorter durations than mothers. One major reason for fathers’ uptake of parental leave is the first reserved month, often called the daddy’s month, introduced in 1995. The reserved month is based on a “use it or lose it” principle, meaning that the month of leave is forfeited if not used by the designated parent. Since the 1990s, two additional reserved months have been introduced to each parent, resulting in a steady increase in fathers’ uptake of parental leave. Nevertheless, some fathers still do not make use of it. We investigate which fathers do not use parental leave and whether this has changed over time. The analysis is conducted with administrative register data of all fathers to children born in Sweden during the years 1994-2017. We especially pay attention to differences between fathers with different earnings, but also the association between the father’s uptake of parental leave and the mother’s earnings. We find that it is more common among fathers with the lowest and highest earnings not to use parental leave compared to other fathers. Over time, this U-shaped pattern has become increasingly clear. This pattern is not visible when considering the mother’s earnings, however. Instead, the likelihood of fathers not using any parental leave decreases when the mother’s income increases, and this pattern persists over time. The patterns of leave use are discussed in relation to the development of the parental leave insurance in Sweden.