Climate-smart agriculture (CSA) is one response to the challenges faced by agriculture due to climate change. As with other sustainability transitions, technological innovation is highlighted as playing a critical role, however, the adoption and diffusion of technological innovations in OECD countries is slow. The aim of this paper is to identify key socio-economic barriers, in terms of supply and demand, that inhibit the adoption and diffusion of CSA technological innovations in Europe. To achieve this aim, a theoretical framework is constructed based on a literature review of socio-economic barriers effecting adoption and diffusion. This framework is explored with data from semi-structured interviews with CSA technology providers and members of agricultural supply chains, such as farmers associations and consumer goods producers (the end-users of the technology). Data was collected on the barriers they experienced, with interviews conducted in the Netherlands, France, Switzerland and Italy. This data was thematically coded and categorised to identify key barrier typologies. The results demonstrate that barriers exist on both the demand (user) and supply (technology provider) sides. The paper provides recommendations for increasing the adoption and diffusion of CSA technological innovations, as well as implications for the CSA and innovation literature.