Théodore-Pierre-Nicolas Maillot was a French painter.

Maillot was born on July 30, 1826 in the former 10th arrondissement of Paris. He was the son of Nicolas Sébastien Maillot, captain adjutant major and painter, and Émilie Carlier. His brother Charles Désiré Claude Maillot was also a painter.

He entered the École des Beaux-Arts de Paris on September 27, 1843, in the studios of François-Édouard Picot and Michel Martin Drolling. He was awarded the 2nd Prix de Rome in 1850 and exhibited at the Salon from 1852.

In 1854, he won the first Grand Prix de Rome with Abraham washing the feet of three angels.

He won a medal at the 1867 Salon and was awarded the Légion d'honneur in 1870.

Until 1876, he sent several portraits, history paintings and religious scenes to the Salon.

In 1882, he married Anne Charlotte Félicie Duban, daughter of Félix Duban.

Théodore Maillot died on June 25, 1888 at his home at 11, rue Marceline-Desbordes-Valmore in the 16th arrondissement of Paris. He is buried in the Montparnasse cemetery (19th division).