In 1905, three teachers and 18 students came together for what would become the American Community School’s first day of class. Back then, the school was created to educate the children of the American families from the American University of Beirut - formerly the Syrian Protestant College. By 1920, the school had expanded and the American Presbyterian Mission joined the AUB in sponsorship of the school; this was when the school was finally renamed the American Community School.
In 1988 the school started enrolling Lebanese students. This resulted from ACS being recognized by the Lebanese Ministry of Education as a distinct entity independent from AUB.
In 1955, ACS received its absolute charter accreditation from the Middle States Association in New York. By 1962 the school was listed as non-profit under (under 501C3).
Today ACS has over 1170 students, representing 70 different nationalities, learning from and working with, over 280 faculty and staff members.