Extreme heat is the deadliest climate hazard in the United States. Climate change and the urban heat island effect are increasing the number of dangerously hot days in cities worldwide and the need for communities to plan for extreme heat. Existing literature on heat planning focuses on heat island mapping and modeling, whereas few studies delve into heat planning and governance processes. We surveyed planning professionals from diverse cities across the United States to establish critical baseline information for a growing area of planning practice and scholarship that future research can build on. Survey results show that planners are concerned with extreme heat risks, particularly environmental and public health impacts from climate change. Planners already report impacts from extreme heat, particularly to energy and water use, vegetation and wildlife, public health, and quality of life. Especially in affected communities, planners claim they address heat in plans and implement heat mitigation and management strategies such as urban forestry, emergency response, and weatherization, but perceive many barriers related to human and financial resources and political will. Planners are concerned about extreme heat, especially in the face of climate change. They are beginning to address heat through different strategies and plan types, but we see opportunities to better connect planners to existing heat information sources and leverage existing planning tools, including vegetation, land use regulations, and building codes, to mitigate risks. Although barriers to heat planning persist, including human and capital resources, planners are uniquely qualified to coordinate communities’ efforts to address the rising threat of extreme heat.