Dr. Michel Welter (19 March 1859, Heiderscheid – 22 April 1924) was a Luxembourgian politician, and former leader of the Socialist Party. A member of Luxembourg's Chamber of Deputies, he served as the Director-General for Agriculture, Commerce, and Industry from 24 February 1916 until 3 January 1917, during the German occupation.
He was one of the fiercest defenders of Victor Thorn's National Union Government. Poorly implemented policies designed to avoid a food shortage back-fired, and the country only narrowly averted a famine. Welter, as the minister responsible for both agriculture and commerce, was held responsible; on 22 December, Welter was censured by the Chamber of Deputies. Although Thorn sought to avoid firing Welter, he was left with no choice, and replaced him with Ernest Leclère.
Born on 19 March 1859 in Heiderscheid to a family of modest means, he studied at several European universities, before settling in Esch-Alzette as a doctor. His work as a physician brought him into contact with the miners and railway workers there, and it was their poor living and working conditions which drove him to take up politics. He campaigned for women's right to vote, paid holidays, social security and decent housing for workers.
In 1896 he was elected to the Chamber of Deputies for the first time, where his social campaigning soon earned him the nickname "de rouden Dokter" (= "the red doctor"). Yet Welter, seen as a radical by the middle-class Deputies, was criticised by the workers for his own middle-class background.
In 1902, Welter moved to Luxembourg city, where he co-founded the Social-Democratic Party. He was Luxembourg's delegate at the Second International and came into contact with Jean Jaurès, Clara Zetkin and August Bebel.