Marlin Edgar Olmsted (May 21, 1847 – July 19, 1913) was a Republican member of the U.S. House of Representatives from Pennsylvania in the 18th district.

He was elected to represent Dauphin County, Pennsylvania, in the proposed constitutional convention in 1891.

He was one of the managers appointed by the United States House of Representatives in 1905 to conduct the impeachment proceedings against Charles Swayne, judge of the United States District Court for the Northern District of Florida.

He died at Manhattan Eye, Ear and Throat Hospital on July 19, 1913, and was buried at Harrisburg Cemetery.

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