Walter Christian Ploeser (January 7, 1907 – November 17, 1993) was a U.S. Representative from Missouri and United States Ambassador to Paraguay and Costa Rica.
He engaged in the insurance business in St. Louis, Missouri, in 1922 and founded his own company in 1933.
He served as chairman of the Select Committee on Small Business (Eightieth Congress).
He served as director of Webster Groves Trust Company.
He was a resident of St. Louis, Missouri, until his death on November 17, 1993.