Maria Pires da Silva Keil do Amaral (Silves, August 9, 1914 - Lisbon, June 10, 2012) was a Portuguese painter and illustrator, associated with the second generation of Portuguese modernist painters. In 1959, at the same time as she executed the tile mural in Infante Santo and the ceramic panels for the buildings in Olivais-Norte, Maria Keil began what was her greatest work in this area: the wall covering of nineteen Lisbon subway stations, all projects developed by the architect Francisco Keil do Amaral, her husband.
Maria Keil signed a vast and diversified body of work including painting, illustration, ceramics, graphic and furniture design, tapestry and set design. Her intense activity as an illustrator, played a crucial role in the renovation of the contemporary tile in Portugal. In 2013 the Museum of the Presidency of the Republic organised a retrospective exhibition covering the multiple aspects of her work.