Today, against the impacts of aging population and the increase in social unbalances and demands, the call to make European cities more inclusive, safe, resilient and sustainable puts the construction of equally distributed well-being conditions at the core of urban regeneration processes. From this perspective, accessibility to city spaces plays a significant role when understood as a right to citizenship, and as a crucial agent of socialisation. This chapter investigates accessibility as a set of spatial conditions allowing people (regardless of their age, gender, health, wealth and social status) to autonomously and sustainably move every day between their houses, public spaces and equipment. The assumption is that taking accessibility as a key attribute of cities helps conceptualise their spatial quality as a “performance feature” to be defined in relation to how individuals concretely act in places, according to their different bodies, needs, perceptions, lifestyles and co-existence habits. By recalling some past and present planning and design theories and practices, different physical and social dimensions of accessibility are questioned. The aim is to show the need to address urban regeneration towards the cities’ transformation into more “place and people sensitive”, inclusive and “proactive” environments.