Marcus Tullius Reynolds (August 20, 1869 – March 18, 1937) was a prominent architect from the Albany, New York area. Born in Great Barrington, Massachusetts, he was raised by his aunt in Albany after the death of his mother. He attended Williams College and Columbia University and began his life as an architect in 1893. He is well known for his bank designs and specifically his design of the Delaware and Hudson Railroad Company Building in downtown Albany. Many of his buildings still stand today, some of which are listed on the National Register of Historic Places. He was the brother of the prominent Albany historian and author Cuyler Reynolds.