William Tod Otto (January 19, 1816–November 7, 1905) was an American judge and the eighth reporter of decisions of the United States Supreme Court, serving as reporter from 1875 to 1883.
Born in Philadelphia, he received his A.B. in 1833 and his A.M. in 1836, both from the University of Pennsylvania. He moved west and practiced law in Brownstown, Indiana and was a judge on the Indiana Second Circuit Court from 1844 to 1852. He taught law at Indiana University and successfully ran for Attorney General of Indiana in 1858. He was a delegate to the 1860 Republican National Convention supporting Abraham Lincoln. Once president, Lincoln made him assistant secretary of the Department of the Interior; he served in that capacity from 1863 to 1871. Otto also was a diplomat, helping arbitrate claims against Spain and a delegate to the Universal Postal Union congress in Lisbon, Portugal.
