The Nis Puk (sometimes also Niß Puk (German: [ˈnɪs pʊk])) is a legendary creature, a kind of Kobold, from Danish-, Low German- and North Frisian-speaking areas of Northern Germany and Southern Denmark, among them Schleswig, today divided into the German Southern Schleswig and Danish Northern Schleswig. It is also known in Denmark itself as nis pug, as a variant of nisse.

An earlier saying says Nissen does not want to go over the Eideren, i.e. not to Holstein to the South of Schleswig. Depending on the place, it can either appear as a domestic spirit or take on the role of a being generally called Drak or Kobold in Danish and German mythology, an infernal spirit making its owner wealthy by bringing them stolen goods.

The term combines the terms Nisse and Puck. The Nis Puk or Niß Puk can also be referred to as just Niß, Nis or Puk. The figure of the Nisse is widespread in Denmark, Norway, Scania, Halland and Blekinge (here as Goanisse or Godnisse≈the good Nisse), the figure of the Puk can further be found in the (formerly) German-speaking regions of Pomerania and Neumark, belonging partially or completely to Poland today.

Variations of its name are Nißpuk, Niß-Puck, Nis Puck, Nis Puk, Nispuk, Niß Pug, Nisse Pok, Neß Puk, Nißkuk or Neßkuk, Nisebok, Nisebuk, Niskepuk or Nische Puk.

Also there are Niß, Niss, Nis, Neß or Nisch. The Danish Nisse (q.v.) appears in earlier times to have been called puge, with medieval attestations, and the Danish form nis pug is also known as variant to nisse in some local folklore (var. nis puge).

Further there are Puk, Puck, Pug, Pûks or Hauspuk (“house Puk”).

Plural forms are Niskepuks, Nisken, Husniskens, Hausnischen (both “little house Nißs”), Husknechtkens (“little house servants”), Puke, Puken, Puge, Pûkse, Pücken or Hauspuken (“house Puks”). and in Danish Nis Pukker

One Pug is known to have had the proper name Bartel.