Urban residents are unequally exposed to environmental and climate-related health risks as a result of unequal relations of power and privilege historically produced along lines of race, ethnicity, income levels, immigration status, gender or age, and their intersections. This chapter examines how the limited access of vulnerable and historically marginalized groups to safe and healthy urban environments and infrastructures (such as green areas, flood-resistant neighborhoods and publicly accessible heat refuges) and their higher exposure to risky ones acts as a driver of urban injustice with direct links to and implications for sustainability. If the goal of urban sustainability is to safeguard human and planetary health, it must address existing health inequalities linked to socioecological systems and urban planning policy and involve those whose health is at risk in decision-making processes to avoid reproducing the same patterns of injustice. We analyze this in the context of sustainability, focusing on two themes: (i) exposure to environmental pollution and toxicity and (ii) the health implications of unequal access to the sustainable city, providing examples of policy approaches that address uneven environmental health patterns as a driver of urban injustice.