William Loughridge (July 11, 1827 – September 26, 1889) was a pioneer attorney, judge, and three-term United States Congressman from Iowa.

After studying law, he was admitted to the bar in 1849 and commenced practice in Mansfield, Ohio.

In the 1866 Republican district convention for Iowa's 4th congressional district, Loughridge upset incumbent Congressman Josiah B. Grinnell, winning (by thirteen votes) the nomination for the U.S. House of Representatives seat then held by Grinnell.

In the 1870 Republican district convention, Loughridge was upset by Madison Miner Walden.

He sought renomination, but in the 1874 district convention ballotting, he finished behind his eventual successor, Ezekiel S. Sampson, and Sampson's successor, James B. Weaver (who had not yet left the Republican Party for the Greenback Party).