There is a risk in the ‘Smart City’ that plural forms of knowing the city become eclipsed by singular governance-oriented analyses produced through computational logics originating from undemocratic service providers. In light of this concern, this chapter considers three aspects of smart urbanism’s knowledge politics: i) the role of urban agencies – or understanding smart urbanism as a situated, socio-material practice; ii) the agency of smart city technologies’ materiality as well as the ownership and control of these technologies, and: iii) the political rationalities, values and assumptions embedded in smart city technologies’ design and use. Drawing on these insights, this chapter analyses smart knowledge politics in Barcelona, where the 2015 council elections replaced a market-oriented political leadership enthusiastically implementing the Smart City with a political leadership whose origins in social movements and citizen democracy made it deeply sceptical towards smart urbanism. We analyse how this opened up space for different approaches to using technology in the city while at the same time giving rise to materially very different kinds of smart knowledge configuring technologies emphasising citizen participation and democratic control of knowledge production. Indeed, political rationalities and smart knowledge configuring technologies intersected and co-evolved, rather than one informing the other unidirectionally.