The literature positions public space as important to cities and society, but it articulates several differ-ent theories regarding what function urban public space should perform. Prior research seldom ex-plores conflicts between these theories or attempts to reconcile them. Further, the ability of public space to mediate sustainability impacts remains under-explored. I respond to these gaps with a two-part study. In the first part, I search the literature for theories of function, which I analyze for syner-gies, conflicts, and sustainability implications. In the second part of the study, I conduct direct spatial observation at five sites in the Stockholm region, and I analyze the results against the theories of function surfaced under Part 1. Throughout, I work in the context of transit-oriented development (TOD), in recognition of the model’s global relevance and explicit sustainability goals.

I find three dominant theories of function for urban public space, which I label ‘Society,’ ‘Economy,’ and ‘Activity.’ I articulate numerous conflicts and synergies among them, for instance that maximiz-ing economic growth may stifle democratic expression. Further, I find that the function(s) which a space fulfills can mediate positive and negative effects on ecological and social sustainability; for in-stance, a commercialized space may incur ecological damage by inducing unnecessary consumption. At the sites I observe, I identify three spatial patterns, which I label ‘Monocentric,’ ‘Polycentric,’ and ‘Town Square.’ In each pattern, I observe a unique profile of alignment to the three theories of func-tion. I conclude that further research should pursue a more holistic theory of function for public space, reconciling conflicts and attending to sustainability. Further, I conclude that planners should devote new critical attention to the function of urban public space so as to better align cities’ material realities with shared values and sustainability needs.