Gustavus Sessinghaus (November 8, 1838 – November 16, 1887) was a U.S. Representative from Missouri.

Born in Koela, Prussia, Sessinghaus pursued preparatory studies. Immigrated to the United States and settled in St. Louis, Missouri. During the Civil War served as a private in Company A, Fifth Regiment, United States Reserve Corps, Missouri Volunteer Infantry. He served as member of the school board 1878-1880. He successfully contested as a Republican the election of Richard G. Frost to the Forty-seventh Congress and served two days only, (March 2, 1883 – March 3, 1883). He was an unsuccessful candidate for reelection in 1882 to the Forty-eighth Congress. He engaged in the milling business. He died in St. Louis, Missouri, on November 16, 1887, and was interred at Bellefontaine Cemetery.