The companions of Saint Nicholas are a group of closely related figures who accompany St. Nicholas in German-speaking Europe and more widely throughout the territories formerly in the Holy Roman Empire. These characters act as a foil to the benevolent Christmas gift-bringer, threatening to thrash or abduct disobedient children. Jacob Grimm (Deutsche Mythologie) associated this character with the pre-Christian house spirit (kobold, elf) which could be benevolent or malicious, but whose mischiveous side was emphasized after Christianization. The association of the Christmas gift-bringer with elves has parallels in English and Scandinavian folklore, and is ultimately and remotely connected to the modern Christmas elf in American folklore.

Names for the "dark" or threatening companion figure include: Knecht Ruprecht in Germany, Krampus in Austria, Bavaria, Croatia, Slovenia, Friuli, Hungary (spelled Krampusz); Klaubauf in Bavaria, Austria; Bartel in Styria; Pelzebock; Pelznickel; Belzeniggl; Belsnickel in Pennsylvania; Schmutzli in Switzerland; Rumpelklas; Bellzebub; Hans Muff; Drapp; and Buzebergt in Augsburg. The corresponding figure in the Netherlands and Flanders is called Zwarte Piet or Black Pete, and in Switzerland Schmutzli, (schmutz meaning dirt). In the Czech Republic, St. Nicholas or Svatý Mikuláš is accompanied by the Čert (Devil) and Anděl (Angel). In France, St. Nicholas' companion is called "Rubbels" in German-speaking Lorraine and Hanstrapp (in Alsace, East of France) and Le Père Fouettard (Wallonia, Northern and Eastern France).