St. Mary's University University (SMU) is an outgrowth of St. Mary's University Language School which was established in 1991 in Addis Ababa.  The Language school was upgraded to a language center in 1995 and has solely been devoted to the imp rovement of the English language proficiency of students, establishing itself as a leading language center in the capital.  It was in this language center that the University was born.

St. Mary's University was established in 1998 under St. Mary's University General Educational Development PLC with its head office in Awassa and a branch in Addis Ababa.

It commenced its operations in the same year with 33 students in Awassa and 37 in Addis Ababa, studying in three departments (Departments of Accounting, Marketing, and Law).  Later the same year, 49 students joined the Dilla Branch, 90 kilometers from Awassa, which is found in the southern part of Ethiopia. In the last quarter of 1998, it admitted more than 300 students in Addis Ababa (Lideta Campus located opposite the Federal High Court) and 25 students in Dilla.

Envisaging the trend of development of the conventional mode of learning, the moved its head office to Addis Ababa, Lideta Campus, in 1999 and opened the Department of Secretarial Science and Office Management (SSOM). With a view to broaden its programs, the Department of Computer Science (initially offering diploma programs) was put in place in September 2000 and the degree program in Law was initiated for the first time in the same year.