Theodorus Willebrordus Maria (Theo) Mackaay is a Dutch sculptor, painter and musician who was born in Utrecht on 19 November 1950. Between 1972 and 1976 he studied at the Gerrit Rietveld Academie in Amsterdam and from 1977 to 1979 he went to the Rijksacademie van Beeldende Kunsten in Amsterdam.

Since 1980 he started his career as a professional painter and sculptor. His figurative work is inspired by Pablo Picasso, Marino Marini and Ossip Zadkine. In 1980 he designed the Gouden Kalf, a sculpture which is awarded at the Dutch Filmfestival.

Mackaay has had various exhibitions in the Netherlands and abroad, including Galerie Morren (Amsterdam, 2015), Carlton Hotel (Cannes, 2015), Amstel Hotel in Amsterdam (2016). Mackaay is also a musician who was a guitarist and singer in various bands.