Taco Mesdag (Dutch pronunciation: [ˈtaːkoː ˈmɛzdɑx]; Groningen, 21 September 1829 – Den Haag, 4 August 1902) was a Dutch banker and painter.
Mesdag, son of the banker Klaas Mesdag and Johanna Willemina, worked with his younger brother Henry in the banking business of his family.
Like his brother Hendrik Mesdag, he eventually also chose to paint as a profession.
Together they played an important part in the Hague School Pulchri Studio, where Hendrik served as president and Taco as treasurer.
Much of his work was donated by his widow, Geesje Mesdag-van Calcar, to the Groninger Museum.