Heathenry, or heathenism, is the worship of the Germanic gods, the Æsir and Vanir (Ases and Wanes). It is the indigenous religion of the Germanic (or Teutonic) peoples (which includes the Anglo-Saxons, Danes, Dutch, Franks, Frisians, Germans, Goths, Icelanders, Lombards, Norwegians, and Swedes) and is therefore technically Germanic paganism, although most heathens prefer to distinguish it from other forms of paganism, especially those that are eclectic and/or magical in focus rather than reconstructionist. Many heathens refer to their religion as Asatru (or Ásatrú), an Old Norse term that was actually coined in the nineteenth century by a Danish scholar. Others reserve that term for Norse-based approaches to heathenry. In many countries, the term Forn Sed (“ancient tradition”) or its equivalent is common. Other names for various approaches to heathenry include Odinism (focused on the god Óðinn/Woden), theodism (based on the traditions of the West Germanic tribes), Armanism (based on the teachings of Guido (von) List and Viktor Rydberg), and Vanatrú (focused on the Vanir more than the Æsir).

Heathenry does not have a central authority, a set of shared dogmas, or a universally recognized priesthood. There are a wide variety of heathen organizations, local, national, and international, many unaffiliated heathens, and many differences in practices and in policies. What unites all heathens is reverence for the gods and the ethics and tradition associated with them.