This paper provides insight into how the conceptualization of urban knowledge sharing has developed. Based on a structured review and categorization of the literature, we identify three forms of knowledge sharing in and between cities that are distinctly different: knowledge transfer, knowledge exchange, and knowledge co-creation. We find that the three forms have different boosts and barriers, whereby the complexities of knowledge sharing and hence the capacities required of the actors are lowest for knowledge transfer and highest for knowledge co-creation. We would therefore like to qualify the recent emphasis given in literature to co-creation; with its complexities and required capacities, it is not to be considered a panacea for solving all urban problems. We propose a model within which knowledge transfer and exchange are more suitable for less wicked problems and may sometimes fruitfully reduce complexities.