Norway reformed its pension system in 2011, introducing a Swedish-style, NDC system. Contrary to expectations, the reform was largely supported by the dominant confederation of trade unions, the LO. In this article, we look at LO involvement in the process at different stages. Through qualitative interviews with key reform architects, we have traced the process between 2005 and 2008, emphasising actors, meeting places and interests. Starting from the insight that unions can influence through lobbying, bargaining and (the threat of) mobilising, we suggest that lobbying can be a mutual process, where parties and unions move each other’s positions. In addition, bargaining can take the form of behind-the-scenes cooperation, as well as of negotiations in the classic, Nordic-style industrial relations sense. Expanding on this framework, we suggest that the literature on pension reforms should pay more attention to negotiated and voluntary labour market occupational schemes, and to the importance of expertise and networks.