The American Association of Petroleum Geologists (AAPG) is one of the world's largest professional geological societies with more than 40,000 members across 129 countries as of 2021. The AAPG works to "advance the science of geology, especially as it relates to petroleum, natural gas, other subsurface fluids, and mineral resources; to promote the technology of exploring for, finding, and producing these materials in an economically and environmentally sound manner; and to advance the professional well-being of its members." The AAPG was founded in 1917 and is headquartered in Tulsa, Oklahoma; currently almost one-third of its members live outside the United States.

Over the years, the activities of the AAPG have broadened so that they bring together not just geology but also geophysics, geochemistry, engineering, and innovative analytics to enable the more efficient and environmentally-friendly approaches to the development of all earth-based energy sources. New transformative technologies, such as the ability to better characterize reservoirs through imaging and the integration of multiple data sources, are coupled with concerns about the environment. Members and affiliated societies are very much involved in preserving the quality of groundwater, dealing responsibly with produced water, and understanding the mechanisms of induced seismicity. In addition to subsurface investigations, the society supports mapping of the surface and the use of new technologies (UAVs, drones, big data analytics), with the goals of advancing the science and understanding of geological processes.

AAPG publishes the AAPG Explorer magazine and AAPG Bulletin scientific journal, and co-publishes a scientific journal with the Society of Exploration Geophysicists called Interpretation. The organization holds an annual meeting including a technical conference and exhibition, sponsors other conferences and continuing education for members around the world such as ongoing Geosciences Technology Workshops, and provides various other services to its members. The organization also includes divisions focused on particular aspects of the profession. These include the Division of Environmental Geosciences, Division of Professional Affairs, and the Energy and Minerals Division. The association membership has included Harrison "Jack" Schmitt, a U.S. astronaut who walked on the moon.