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. Her first recital was at the age of five, and at the age of seven she was already playing Mozart piano concertos publicly. Two years later she received Portugal's top prize for young musicians.