Kettler is a surname of Germanic origins, particularly in Germany and Austria. Notable people with the surname include: Donald Joseph Kettler (born 1944) Catholic Bishop of St Cloud. Ferdinand Kettler (1655–1737) Duke of Courland Frederick Casimir Kettler (1650–1698) Duke of Courland Gotthard Kettler (1517–1587), founder of the Duchy of Courland Jacob Kettler (1610–1682) Duke of Courland Robert C. Kettler, Washington D.C. area real estate developer (1952- current) Wilhelm Kettler (1574–1640) Duke of Courland Frederick William, Duke of Courland or Friedrich Kettler (1692–1711) House of Kettler Noble House See also Ketteler Low German surnames Germanic-language surnames Occupational surnames