St. Mother Teresa High School is a Catholic secondary school in the Nepean district of Ottawa, Ontario, Canada. It is part of the Ottawa Catholic School Board (OCSB). It supports grades 7–12'. The motto of the school is Amor et Dignitas or "love and dignity."

Mother Teresa has many sports teams, including alpine skiing, badminton, baseball, basketball, cross country running, curling, field hockey, golf, hockey, lacrosse, Ski Club, soccer, swimming, softball, field lacrosse, swimming, tackle football, track and field, varsity girls touch football, volleyball and wrestling.

On May 28, 2014, the OFSAA division baseball team won the NCSSAA city championship giving the school its seventh city championship win of the school year.

Mother Teresa's Drama Department put on a production of twinkly stars in 2015.

Mother Teresa has a diverse selection of official lunchtime clubs that include, Key Club, Eco Club, Business Club, Trivia Club, Makerspace Club and Math Club.

Mother Teresa offers several lunchtime clubs for minority groups including the Latino Hispanic Student Association, Black Student Association, Rainbow Alliance, Asian Student Association, Muslim Student Association and Indigenous Student Association.

On May 26, 2011, an empty barrel of peppermint oil exploded in an auto-shop class, killing 18-year-old student Eric Leighton, a hockey player with the Almonte Thunder, as well as causing minor injuries to four other students and one staff member.

On 4 September 2016, the school's patron Mother Teresa was canonized into Sainthood by Pope Francis. She is now referred to as Saint Teresa of Calcutta in the Catholic Church. The Ottawa Catholic School Board decided to rename the high school, St. Mother Teresa Catholic High School to keep with tradition.

• Education in Ontario
• List of high schools in Ontario
• List of Ottawa schools

• 150 years of Catholic Education in Ottawa-Carleton 1856-2006, Ottawa-Carleton Catholic School Board, 2006

• Official website