Maria João Alexandre Barbosa Pires (born 23 July 1944) is a Portuguese classical pianist, widely regarded as one of the leading interpreters of the repertoire of the 18th and 19th centuries.

Pires was born in Lisbon, Portugal, a posthumous daughter of João Baptista Pires and his wife Alzira dos Santos Alexandre Barbosa. She has three siblings: Hugo Alexandre Barbosa Pires, Maria Regina Alexandre Barbosa Pires and Maria Helena Alexandre Barbosa Pires.