The American Physical Society was founded in 1899 and is the world's second largest organization of physicists, behind the Deutsche Physikalische Gesellschaft. The Society publishes more than a dozen science journals, including the world renowned Physical Review and Physical Review Letters, and organizes more than twenty science meetings each year. Over 46,000 members belong to the Society.

The American Physical Society was founded on May 20, 1899, when thirty-six physicists gathered at Columbia University for that purpose. They proclaimed the mission of the new Society to be "to advance and diffuse the knowledge of physics", and in one way or another the APS has been at that task ever since. In the early years, virtually the sole activity of the APS was to hold scientific meetings, initially four per year. In 1913, the APS took over the operation of the Physical Review, which had been founded in 1893 at Cornell University, and journal publication became its second major activity. The Physical Review was followed by Reviews of Modern Physics in 1929 and by Physical Review Letters in 1958. Over the years, Phys. Rev. has subdivided into five separate sections as the fields of physics proliferated and the number of submissions grew.

In more recent years, the activities of the Society have broadened considerably. Stimulated by the increase in Federal funding in the period after the Second World War, and even more by the increased public involvement of scientists in the 1960s, the APS is active in public and governmental affairs, and in the international physics community. In addition, the Society conducts extensive programs in education, science outreach, and media relations. The APS has fourteen divisions and nine topical groups covering all areas of physics research. There are six forums that reflect the interest of its 46,000 members in broader issues, and eight sections organized by geographical region.

In 1999, the APS celebrated its Centennial with the biggest-ever physics meeting in Atlanta. In 2005 the APS took the lead role in United States participation in the World Year of Physics, initiating several programs to broadly publicize physics during the 100th anniversary of Albert Einstein's annus mirabilis. Einstein@Home, one of the projects the APS initiated during World Year of Physics, is an ongoing and popular distributed computing project.

In 2007, the APS adopted an official statement on climate change:

Emissions of greenhouse gases from human activities are changing the atmosphere in ways that affect the Earth's climate. Greenhouse gases include carbon dioxide as well as methane, nitrous oxide and other gases. They are emitted from fossil fuel combustion and a range of industrial and agricultural processes.

The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now."