The global trend towards the growth of urban population poses the issue of the public space influence on outdoor practices of different subjects. Urban public space is the carrier of an ever-increasing number and density of users. Walking, both as a form of transportation and as a vector to physical activity and social interactions, emerges as a fundamental category of behaviour. The proposed research develops a theoretical and methodological framework for assessing walkability of the urban space. Building on concepts of capability and affordance, walkability is herein conceptualized in terms of the effect of affordances incorporated into the built environment on individuals’ propensity to walk for different purposes. The methodological framework aims to capture the characteristics of walkability across scales as the product of the intrinsic and extrinsic properties of an urban setting.