Conventional theoretical models of the welfare state have difficulties in accounting for the recent expansion of family policies in mature welfare states. This article uses an idea-centred approach, the Advocacy Coalition Framework (ACF), to understand recent family policy change in Switzerland. In a review of conflicts over the introduction of paid maternity leave as well as child day care during the 1990s, two competing advocacy coalitions were identified. The first coalition aimed at restricting government programmes to the prevention of poverty of families, whereas the second advocated the inclusion of measures for the promotion of gender equality. Towards the end of the 1990s, some members of the first advocacy coalition revised their policy core beliefs and changed coalitions, as a consequence of cognitive framing strategies pursued by gender equality advocates. This led to a power shift within the family policy subsystem, resulting in major change of government programmes at all state levels. It is concluded that, on the basis of the ACF, family policy expansion can be coherently traced back to value orientations and cognitive processes.