William Alexander Cant (December 23, 1863 – January 12, 1933) was a United States federal judge.
Born in Westfield, Marquette County, Wisconsin, Cant received an LL.B. from the University of Michigan in 1885. He was in private practice in Duluth, Minnesota from 1886 to 1895. He was a member of the Minnesota House of Representatives in 1895, and was city attorney of Duluth from 1895 to 1896. He was a state court judge on the District Court of Minnesota from 1896 to 1923.
On May 21, 1923, Cant received a recess appointment from Warren G. Harding to a seat on the United States District Court for the District of Minnesota vacated by Page Morris. Formally nominated on December 15, 1923, Cant was confirmed by the United States Senate on January 15, 1924, and received his commission the same day. Cant served in that capacity until his death, in 1933.