St. Mary’s Academy is located on eleven and a half acres in a park-like setting in the heart of Winnipeg. The original five-story building, with the main entrance facing Wellington Crescent, opened in 1903. Today this building is used primarily for offices and work space for the school staff and the Sisters of the Holy Names. It also includes Holy Names Chapel and a 100-seat auditorium.

In 1909 a larger building was attached that still houses most of the 21 classrooms as well as the Richardson Science Wing, the human ecology department and a computer lab. Recent renovations and upgrades to meet building code standards and to enhance programs left intact the traditional architecture wherever possible, but also incorporated up-to-date technology, furnishings and equipment, and resulted in a more comfortable learning environment with improved lighting and air-conditioning.

A new wing, which opened in 1964, was inspired by a desire to enrich the school culturally. It includes Alumnae Hall, the Sister Rita Maureen Gym, a cafeteria and a drama classroom. The gym is home to the St. Mary’s Academy Flames while Alumnae Hall, a 625-seat theatre, houses drama productions, assemblies, school Masses, and meetings. An expansion of this wing is currently underway. In 2010 the new Durocher Library, new fine arts studio and a fitness room opened. Plans for a theatre production wing, multi-purpose room and expanded entrance are underway.