Thomas Duncombe Dee (November 10, 1844 – July 9, 1905) was an American businessman from Utah.

In 1876, he joined industrialist David Eccles and Hiram Spencer in founding businesses in the western U.S., ranging from sugar to lumber to water and shoes and banking.

On July 3, 1905, he slipped into the water while inspecting a potential site for a dam, contracted pneumonia, and died.

For almost two decades preceding his death, he served as a counselor to the bishop of the Mound Fort Ward.

Among several other civic positions, Dee served as a member of the Ogden City Council.