Mary Louisa Matthews (August 28, 1864 – December 31, 1950) was an American educator and missionary.
She taught and was in charge of a Protestant girls school in Monastir (now known as Bitola), a city in the Macedonian region of Ottoman Turkey, from 1888-1920.
She was there through the waning years of the Ottoman Empire, the Young Turk Revolution, Balkan Wars I and II and World War I.
She left detailed records of her observations of the turbulent affairs of the region during the thirty-two years she spent there.
In 1937, her bravery during World War I was recognized when she was among the first group of women to receive the Alumnae Medal of Honor from Mount Holyoke College.
She also received a commendation from the State Department for exceptional service to United States interests during World War I.