The Kyburg family (/ˈkaɪbɜːrɡ/; German: [ˈkyːbʊʁk]; also Kiburg) was a noble family of grafen (counts) in the Duchy of Swabia, a cadet line of the counts of Dillingen, who in the late 12th and early 13th centuries ruled the County of Kyburg, corresponding to much of what is now Northeastern Switzerland.

Kyburg castle, southeast of Winterthur (in the modern canton of Zürich), passed on to the Swabian counts of Dillingen.

The Kyburg family acquired the allodial title to the Vogtei of Windegg or Gaster (today 7 municipalities in the See-Gaster Wahlkreis of St. Gallen) and land around Baden.

Later additional Lenzburg territories, the Schänis Abbey and Beromünster, were also acquired by the House of Kyburg.

They also appointed many of the Lenzburg, and later Zähringen, vassals to be unfree knights or Ministerialis for the Kyburg family.

From the Zähringen line the Kyburgs acquired land west of the Rhine and in Burgundy including the cities of Fribourg, Thun and Burgdorf as well as estates in the canton of Zurich.

However, the House of Hohenstaufen, the family of the Holy Roman Emperors, refused to support the Kyburg claims on the city of Zurich and in 1226 on the Abbey of St. Gall.

As a result, they turned increasingly away from the Hohenstaufens and in 1243 and were one of the mainstays of the pro-Pope and anti-Holy Roman Emperor Party.

Bern took the opportunity to assert its interests in Aargau against the Habsburgs, and after the Bernese laid siege to Burgdorf, Neu-Kyburg was forced to concede an unfavourable peace.

From this time until the French invasion in 1798, the territory was a bailiwick (Landvogtei) administered by a total of 59 successive reeves (Landvögte).

The town of Winterthur remained with Habsburg until 1467, when it was bought by Zürich and treated as a separate jurisdiction.

With the creation of the modern Canton of Zürich in 1831, Kyburg lost its administrative role, and the castle was sold to one Franz Heinrich Hirzel of Winterthur who intended to use it as a quarry.