Maria Stefan (later Mihoreanu, and Cosma, born 16 February 1954) is a retired Romanian sprint canoer who competed at the 1976, 1980 and 1984 Olympics.
She won a gold medal in the K-4 500 m event in 1984 and placed fourth-fifth in the singles in 1976 and 1980.
She won three bronze medals at the ICF Canoe Sprint World Championships, one each in the K-1 500 m (1983), the K-2 500 m (1981), and the K-4 500 m (1983) events.
Her sister-in-law Maria Nichiforov is also a former Olympic canoer.