Thomas Madsen-Mygdal (24 December 1876 – 23 February 1943) was a Danish politician from Venstre who served as the prime minister of Denmark from 1926 to 1929.

Madsen-Mygdal was born in Mygdal, Vendsyssel, the son of landstingsmand, statsrevisor N.P.

He became a teacher from Jelling Seminarium but later studied agriculture.

His government had the parliamentary support of the Conservative People's Party, but he lost their support in 1929 when the Conservative People's Party was not satisfied with the resources allocated to the military in the budget.

Having lost his parliamentary support on this important issue, new elections were held, and the Social Democrats and the Danish Social Liberal Party came into power.