Straw bale building is an environmentally friendly building technique that has not yet reached the broad masses of the population. This thesis seeks answers to why straw bale building has not diffused more, using Everett M. Rogers renowned theory about diffusion of innovations. Qualitative research provides data about the attributes of this particular innovation, characteristics of early adopters of the innovation, as well as other aspects like communication channels and the social context, which could tell us something about why it has not become more popular. Perceptions and experiences about straw bale building in Norway and Denmark are examined through eight interviews with both straw bale builders and straw bale experts. A comparative analysis of Norway and Denmark is also provided. The main findings are that straw bale building s complexity, time- and labour-intensiveness, and its connection to an alternative lifestyle, are factors that are hindering the innovation s diffusion. There is also a lack of information and knowledge about it in society. The thesis argues that if straw bale building is to become a viable option for a larger portion of the populations of Norway and Denmark, the reasonable way forward is its industrialization.