The American College of Sofia (ACS) (Bulgarian: Американски колеж в София) is a school in Bulgaria, located in the capital city of Sofia.The college was founded in 1860 and is regarded as the oldest American educational institution outside the United States.

Founded in 1860 in the then-Ottoman Empire, it was initially a boys' school in Plovdiv, established by American missionaries of the Congregational Church.

[2] By co-operating with a girls' school in Stara Zagora founded by the same people, the American College was established and moved to Samokov in 1871.

As of 2005[update], the American College of Sofia has 606 Bulgarian and 33 foreign students and has enrolled over a thousand, with 848 graduating.

[4] The former president of the American College of Sofia is Thomas Cangiano, former Cleve Housemaster and History Master at the Lawrenceville School.

The campus consists of seven academic buildings,[5] a student dormitory, faculty housing and various sports facilities.