The World Health Organization defines Health in All Policies (HiAP) as "an approach to public policies across sectors that systematically takes into account the health and health-system implications of decisions, seeks synergies, and avoids harmful health impacts, in order to improve population health and health equity. The HiAP approach is founded on health-related rights and obligations. It emphasizes the consequences of public policies on health determinants, and aims to improve the accountability of policy-makers for health impacts at all levels of policy-making".

The elements of HiAP fall under 5 areas:
1. Engaging non-health sectors, community, and private sector stakeholders
2. Research and data
3. Analytical toolkits
4. Laws and formal frameworks
5. Communications

Health Impact Assessments (HIA) are a popular tool used to implement HiAPs. HIAs help advise policy questions by using domains such as data, research, stakeholder engagement, and legal structures.

Many big cities across the United States, such as Seattle, Los Angeles and Nashville, have had success implementing HiAPs and in turn creating healthier communities.

The goal of Health in All Policies is to ensure that health effects are routinely taken into consideration when developing policy.

Health in All Policies initiatives have helped create healthier communities through implementing policies with health consequences in mind. For many counties, this includes creating cross-agency teams and workgroups to address problems in their community.

Results of implementing HiAP initiatives include increased awareness of health impacts when creating policy through the use of interdepartmental teams, establishing new partnerships and healthier communities.

The Boston Public Health Commission created a HiAP task force to address the growing interest in healthy community design. The task force, involving members from city agencies and community organizations, has worked with the transportation department to initiate the Complete Streets guidelines. Complete Streets is an initiative developed to replace the city's taxi cabs with hybrid vehicles, facilitate a health impact assessment (HIA) to inform neighborhood redevelopment and focus on other community design activities.

Similarly, San Francisco established a Program on Health, Equity, and Sustainability, through partnerships with the transportation agency and other agencies, the program has been a part of reducing pedestrian injuries, and addressing food access and housing affordability.