Urban development interventions in a variety of sectors, including in transport, housing, land-use planning, waste management, and energy can generate substantial health benefits to affected communities. These opportunities for health can be overlooked and unnecessary health risks and costs caused and potential benefits foregone if health issues are not explicitly considered as part of urban projects, plans, and strategies. Environmental health assessments bring together inputs from science and experience using a range of approaches, including community consultations and assessment of local environmental conditions to determine how local projects, plans and policies can improve population health. Formal environmental health assessments then stand to help guide thinking about how environmental factors can create health in cities, and provide a voice for children and other groups whose perspective is often not included in decision making. This chapter provides an introduction to environmental health assessments with an eye to equipping local actors to proactively contribute to creating health and health equity among urban populations, as a key tool for including Health in All Policies.