Henry Theodore Olmsted (January 12, 1879 – January 6, 1969) was a starting pitcher in Major League Baseball who played briefly for the Boston Americans during the 1905 season. Listed at 5 ft 8 in (1.73 m), 147 lb., Olmsted batted and threw right-handed. A native of Sac Bay, Michigan, he attended University of Notre Dame and Valparaiso University. He later played for the Denver Grizzlies in the Western League.
Olmsted posted a 1–2 record with a 3.24 ERA in three appearances, including three complete games, six strikeouts, 12 walks, 18 hits allowed, and 25.0 innings of work.
Olmsted died in Bradenton, Florida at age 89.