The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of the organization. It is a 501(c)(3) organization with a membership of more than 60,000 obstetrician-gynecologists and women's health care professionals.^[1] It was founded in 1951.

A companion 501(c)(6) organization, the American Congress of Obstetricians and Gynecologists, was founded in 2008 and became operational in 2010.^[2] The two organizations coexist, and member individuals automatically belong to both.^[3] Both are not-for-profit.^[3] The College as a 501(c)(3) focuses on education (with limited political work), whereas the Congress as a 501(c)(6) is allowed to advocate for members' interests in terms of the business of medicine (BOM) through lobbying and other political work.^[3] Their main advocacy focuses on women's reproductive health, specifically opposing political interference in abortion access.^[4] Physician members are referred to as fellows and use the post-nominal letters FACOG to indicate their status. To become a fellow, a candidate must become certified by the American Board of Obstetrics and Gynecology,^[5] an independent organization, and then nominated to the College by another fellow. Non ObGyn professionals may join as an Allied Health Professional, but must meet their standards of education.^[6]

Obstetrics & Gynecology is the official publication of ACOG. It is popularly known as "The Green Journal".^[7] In 1986, the organization successfully challenged an anti-abortion law in Pennsylvania before the U.S. Supreme Court in Thornburgh v. American College of Obstetricians and Gynecologists.^[8]