Abstract. Health and environmental psychology have long been walking side by side. These two disciplines of psychology have imported and applied common psychological frameworks and each of them developed specific theories and methodologies. At a time when humankind faces tremendous challenges ahead (climate change, global warming, ocean sickness, the reemergence of infections pandemics), environmental health is more and more a crucial domain of research. Both environmental psychology and health psychology need to be engaged in environmental health issues in order to enhance planetary health. Environmental psychology traditional fields of research provide understanding about how natural or constructed environments impact human identity, attitudes, and behaviors (more recently, environmental psychology is also investing in determinants of pro-environmental behaviors). On the other hand, health psychology has an extensive comprehensive framework about how to promote healthy habits (i.e., automatically activated behaviors). We live in a global and extremely complex and interconnected world, which promotes syndemic phenomena (several interactive epidemics sharing common etiological factors), also resulting in accelerated depletion of natural resources. This current scenario might justify the development of an Environmental Health Psychology discipline, joining together tools from both environmental psychology and health psychology in a synergic and strategic way.