Uradel (German: [ʔuːɐ̯ˈʔaːdl̩], German: "ancient nobility"; adjective uradelig or uradlig) is a genealogical term introduced in late 18th-century Germany to distinguish those families whose noble rank can be traced to the 14th century or earlier. The word stands opposed to Briefadel, a term used for titles of nobility created in the early modern period or modern history by letters patent. Since the earliest known such letters were issued in the 14th century, those knightly families in northern European nobility whose noble rank predates these are designated Uradel.

Uradel and Briefadel families are generally further divided into categories with their ranks of titles: adlig (untitled nobility), freiherrlich (baronial), gräflich (comital), fürstlich (princely) and herzoglich (ducal) houses. The latter two are also referred to as Hochadel (High Nobility).

The first use of the word Uradel to designate the oldest nobility dates from 1788, and it had assumed its present-day meaning by no later than 1800. The term Uradel was used officially from the 19th century by the Royal Prussian Herald Office (königlich-preußische Heroldsamt). The term is found in the Almanach de Gotha from 1907, in which it is applied to all persons and families known to have been "noble" or "knightly" before 1400. The subsequent German-language publications Genealogisches Handbuch des Adels (GHdA) and since 2015 the Gothaisches Genealogisches Handbuch continue to differentiate between Uradel and Briefadel families.

According to the German genealogical reference work of the nobility (Genealogisches Handbuch des Adels, 1951) the noble houses which count as Uradel are those families whose ancestral lineage can be demonstrated to date at least as far back as the year 1400 (in the Late Middle Ages), belonging at that time to the knightly (German ritterbürtigen) nobility.

The latter includes edelfreie families (free noblemen) as well as ministeriales, a lower and in their origins mostly unfree order which arose rapidly and managed within the 14th century to elevate themselves to the lesser nobility (see: Estates of the realm). The modern concept of aristocracy (Uradel) must not be confused with the term edelfrei, since the former term's scope is much broader: all families that can prove they belonged to the knightly aristocracy by no later than around 1400 (whether originally edelfrei or ministeriales) are counted today as Uradel. In fact, most of the families in the former Uradel volumes of the Gotha are of ministerialis origin, including even some of the later princely houses ("Hochadel", see below).

Edelfrei families were members of an ancient, dynastic aristocratic line, free noble families independent of legal obligations of a secondary nature, and they were not subordinated to any other families or dynasties, apart from the German King or Holy Roman Emperor. In contrast, the ministeriales, meaning originally "servitors" or "agents", were unfree nobles, however trained knights who made up a large majority of what could be described as the German knighthood during that time. These people were raised up from serfdom to be placed in positions of power and responsibility in the service of lords, counts or bishops. From about 1200 they gradually accumulated power and fiefs, at some point more than the Edelfrei knights. Poorer Edelfrei knights passed into ministerialis service, primarily to be granted new administrative positions and fiefs. The powerful overlords, mostly edelfrei themselves, had no interest in raising any competition to their power by sharing it with their peers, rather attempting to subject these by making them their vassals. In the 14th century, the edelfrei and ministerialis classes finally mixed and intermarried. Those ministeriales who directly served the German king or emperor (the "ministeriales of the Empire" or Reichsministerialen) often accumulated large imperial fiefs, later sometimes enabling them to rise to comital or princely rank.

Ministeriales mostly rose by elevation to the knightly status. Knightings were usually granted to squires having bravely fought as armored horsemen in a battle, yet sometimes also to simple men-at-arms. A ministeriales family however was considered a "knightly family" only after three subsequent generations of knights (or at least of leading a "knightly way of life", including equal marriage). Since it is a coincidence from what period of time documents have been received or not, the initially more strict definition, as described in Der Große Brockhaus in 1928 (vol. 1, s.v. "Adel"), which required an attestation prior to the year 1350 to establish Uradel status, has been extended to the year 1400 because even the knightly families documented as dating from the Late Middle Ages (between about 1350 and 1400) are likely to have had already at least a century of possessing that status. Many have in fact risen to noble or knightly status already before 1300.

Uradel is also closely connected with the system of medieval fiefs, granted by an overlord to a vassal who held it in fealty (or "in fee") in return for a form of feudal allegiance and service, usually given by the personal ceremonies of homage and fealty. Therefore feudal deeds are an important source not only for the existence of noble families, but also for their rank and status. Witness lists, for instance, mostly enumerate edelfreie witnesses first, followed by ministeriales witnesses, mostly denoted as eques (knight) or something similar.