Stanley Wilmer Slagg (July 6, 1903 – December 22, 1978) was an American lawyer and politician from Edgerton, Wisconsin, who served two terms as a Republican member of the Wisconsin State Assembly, and afterwards repeatedly ran for various elective offices, either as a Progressive or as a Republican.
He was appointed an assistant district attorney in Dane County in 1926 by Philip La Follette.
Slagg won the Republican primary election for the first Rock County Assembly district (Blanchard's former seat) in 1928, receiving 3,683 votes to 2,836 for Thomas S. Nolan.
By 1942, he had returned to the Republican Party, and sought (unsuccessfully) nomination to the State Senate; in 1948 and 1950, to the Assembly (in both cases losing again to Grassman); and in 1952 for the Assembly, losing to eventual victor Clyde Jewett (Grassman was not a candidate).
At the 1952 Republican Party 1st Congressional District convention, he was one of the few delegates arguing for one man one vote reapportionment of the State Senate.