This study contributes to the growing literature on the domestic politics of climate change by examining the climate policy preferences of Fianna Fáil, Fine Gael and the Labour Party over 20 years. Bringing the concept of ‘policy entrepreneurship’ into the study of intra-party politics, it uses secondary data, party documents, publicly-available information and a series of in-depth interviews to develop an understanding of intra-party policy entrepreneurship and political parties’ climate policy preferences. It finds that office-seeking incentives have tended to trump the activities of individuals who have engaged in policy entrepreneurship with the aim of strengthening their parties’ climate policy preferences. In instances where office-seeking incentives for climate policy have been strong, they have often contributed to changes in policy preferences, whether or not intra-party policy entrepreneurship has been present. Theoretically, the study argues that the concept of ‘policy entrepreneurship’ can be usefully borrowed from the public policy literature by researchers of party policy preferences and intra-party politics. Empirically, it adds to the small but growing body of research on climate politics in Ireland.