The term 'heathenry' can be used to denote both the ancient pagan religion of the Germanic peoples and modern reconstructed versions of that religion such as Ásatrú. The linguistic/anthropological term 'Germanic' refers to a group of Northern European tribes who at one point shared a common language, culture and religion. By the year 500 CE, the Germanic culture had spread out into the areas of Europe which were to become present day Denmark, Norway, Sweden, Germany, Holland, and England. By the year 700 CE, the various dialects of the common- Germanic language were becoming mutually unintelligible and evolving into German, Dutch, English, and the Scandinavian languages.

The information that has come down to us about the pre-Christian religion of the Germanic peoples spans a wide range in terms of time and place. The religion of the tenth century Icelanders as described in the sagas is notably different from the religion of the Germanic tribes bordering the Roman Empire as described by Tacitus-- although a comparison between the two yields a continuous core of belief at a deeper level. Some modern heathen groups focus on the common threads throughout all incarnations of Germanic paganism. Others focus on the heathen practices of a particular place and time, such as Anglo-Saxon England or Viking Age Iceland. The sources and evidence for the actual beliefs and practices of the pre-Christian Germanic peoples are subject to a great deal of interpretation and reinterpretation by philologists, archaeologists, and historians and are being examined by new academic disciplines all the time. The continuing scholarly debate allows modern heathen groups a measure of leeway in determining which religious practices are "authentic".

Heathenry, like all ancient European pagan religions, is polytheistic. Heathens recognise numerous sentient entities, generally referred to as 'wights'. In addition to humans, these include major gods, local gods, ancestral spirits, and various sorts of beings familiar from Germanic folklore (elves, brownies, trolls, etc.). Heathens regard all these entities as real parts of the natural world, distinct individuals capable of independent thought and action, just as humans themselves are. Wights are understood to vary in their concerns and behavior on the basis of mood, character, and circumstance, and two wights of the same kind may have very different personalities. Individual heathens may form various sorts of mutually beneficial relationships with any number of particular wights of their acquaintance. One heathen might be oath-bound to Thor and leave offerings for his house brownie, another might honour her disir (female ancestral spirits) on a regular basis, another might work closely with the class of gods known as the Vanir.

Many of the gods honoured by heathens are well known from 'Norse Mythology': Odin, Frigg, Thor, Tyr, Freya, etc., however it is misleading to think of heathen gods as Scandinavian, since some of them were widely recognised throughout the Germanic world. The god known to early Germanic tribes as Woðanaz became Oðin in Old Norse, Woden in Anglo-Saxon and Old Saxon, and Wuotan in Old High German. Some deities recognised and honoured by heathens today were never known in the Scandinavian countries, for example the Anglo-Saxon goddess Eostre, the German goddess Holda, and the Dutch goddess Nehalennia.

One of the central concepts in Heathenry is wyrd, the force that connects everything in the universe throughout space and time. Heathens believe that all of their actions can have far reaching consequences through the web of wyrd. They understand that who they are, where they are, and what they are doing today is dependent on actions they and others have taken in the past, and that every choice they make in the present builds upon choices they have previously made.

With an understanding of wyrd comes a great responsibility. If we know that every action we take (or fail to take) will have implications for our own future choices and for the future choices of others, we have an ethical obligation to think carefully about the possible consequences of everything we do. Thus one of the principal ethics of Heathenry is that of taking responsibility for one's own actions. Heathens strive to live up to the Germanic heroic ideals of honour, courage and hospitality. They are expected to be true to their word and keep all sworn oaths.

The main heathen religious rite is called a blót (rhymes with 'boat'). In ancient times, a blót was a ceremonial animal sacrifice. Blóts were held to honour and thank the gods and ancestors or to gain their favour for specific purposes such as peace, victory, or good sailing weather. Blood from the sacrificed animal was sprinkled upon statues of the gods and upon all present as a blessing. The meat was cooked and shared at a community feast. It would be highly impractical for modern heathens to blót the ancient way, since the skills necessary to humanely slaughter an animal are no longer routinely taught in our society and the circumstances under which animals can be killed for meat are highly regulated. Modern heathens have therefore replaced the animal offering with an offering of mead. Germanic peoples associated mead with blood and saw it as blessed and holy. (In the mythology, the blood of a wise being called Kvasir was mixed with honey to create mead.) During a modern blót, mead is ceremonially poured for a god (into an offering bowl, onto a fire or onto the earth). Sometimes it is also sprinkled on the participants. A feast usually follows.

Sumbel is a heathen ritual drinking ceremony based on the ancient Germanic tradition of the drinking of the minni (memory cup). Sumbel usually takes place following a blót. Mead or ale is ritually blessed. Depending on group preference, either a horn containing the blessed mead is passed to all the participants in turn, or the blessed mead is poured into each participant's individual drinking vessel. Rounds of toasting follow with gods and ancestors being named and honoured. During sumbel, participants may also boast about deeds they intend to accomplish. Such boasts are seen as public promises and the boaster is held accountable by all present, including the gods. Sacred words spoken over the sumbel horn are drunk down with the mead and become part of the wyrd of the speaker and other participants.

Local heathen groups are most commonly called kindreds or hearths (in English speaking countries). Most consist of around five to fifteen members. Some groups have formal membership criteria which may include asking new members to swear certain oaths. Others are completely informal. Some kindreds or hearths are led by a priest or priestess called a godhi or gydhja (Old Norse terms meaning, roughly, 'god-man' or 'god-woman'). A person identified as a godhi or gydhja may have received formal credentials after completing a training program with one of the national (or international) heathen organisations. (Some countries or states accept credentials from major heathen organisations and grant godhis and gydhjas the same rights as recognised clergy from other religions.) Alternatively, a person may become known as a godhi or gydhja simply by being accepted by their hearth or kindred as the best person for the job. Many kindreds believe that all heathens are capable of acting as priests. In such groups the members share out organisational duties and take it in turns to lead rites.

Kindreds and hearths hold celebrations based around blót, sumble and feasting at rites of passage (such as weddings or baby-namings), seasonal holidays, oath-takings, rites in honour of a particular god or gods, and rites of need (in which the gods are asked for help). Some groups meet for a blót on a monthly basis while others celebrate together only a few times a year. Different heathen groups observe different seasonal holidays, depending on their cultural/religious focus. The three most widespread heathen holidays today are Winternights, an autumn feast heralding the end of the agricultural season and the coming of winter; Yule, a twelve day celebration beginning on (or near) the winter solstice; and a feast of the goddess Eostre (or Ostara) in the spring.