The longstanding debate around the merits of promoting social class mix in urban neighbourhoods has taken a new twist in recent times. A transatlantic and neoliberal convergence of policy advice, supported by the ‘neighbourhood effects’ thesis, makes a case for addressing deep poverty by spatially deconcentrating it, inter alia, by gentrification. While developing trenchant critiques of this approach, critical urban scholarship has tended to take a ‘top-down’ view of urban neoliberalism, giving insufficient consideration to the agency of local governance actors in policy design and implementation, as well as to differences in national and local reference points with regard to what social mix connotes. We present findings of a comparative study of the meanings and effects attributed to social mix by key local policy actors across three ‘distressed’ neighbourhoods: in inner-city Paris (France), Bristol (UK) and Montréal (Canada), targeted for neighbourhood revitalization involving planned residential social mix in two cases and diversification of local retailing and its consumer base in all three. We find that while local actors' rationales for social mix do reflect a neoliberal turn, this is not embraced unequivocally and a strong home-grown element, drawing on national or local ‘myths’, persists. Our study sheds light on the expectations that local policy actors have on the incoming middle classes to make the mix ‘work’ by supporting community; pointing to the paradoxes and limitations of such a perspective.