Finland seems to suffer from a kind of ‘policy amnesia’ when it comes to the topic of housing cooperatives. Tracing back from 1920 to 2020, this article analyses waves of experimentation and political debate with housing cooperativism across both housing production and consumption. Supplementing a document analysis with expert interviews, it investigates which cooperatively-organized modes of housing provision were able to institutionalize in the Finnish housing system, when, and why this did (or did not) happen, and what roles they have played in the broader housing regime. It argues that, whilst building cooperatives grew into large and powerful actors in the Finnish housing system, cooperative tenure has never managed to expand beyond a niche mode of housing provision. This article investigates why, and suggests three interrelated factors: the relationship between housing cooperatives and Finland’s ideologically fragmented cooperative movement, the pragmatic and piecemeal reform of Finnish housing policy and politics, and the co-optation and ‘companization’ of cooperative identity.