The aim of this letter is to raise some critical concerns and gaps in the booming literature on Smart Cities; concerns that we think deserve greater attention from scientists, policy makers and urban planners. Using an urban ecology lens, we provide some reflections that need to forgo any wider-scale imple- mentation of the Smart City-model with the goal to enhance urban sustainability. We discuss that the Smart City literature must better include analysis around social sustainability issues for city dwellers. Focus here should start on health issues and more critical analysis about whom the Smart City is for. Also, the literature must address issues of resilience and cyber security, including how Smart City solutions may affect the autonomy of urban governance, personal integrity and how it may affect the resilience of infrastructures that provide inhabitants with basic needs, such as food, energy and water security. A third major gap in this literature is how smart city developments may change human-nature relations. Focus here should start on how Smart City technologies may hinder or support children’s learning towards a stronger psychological connection with nature. Discussions are also needed on how the Smart City model may affect pro-environmental behavior more broadly.