Thun Castle is a castle in the city of Thun, in the Swiss canton of Bern. It was built in the 12th century, today houses the Thun Castle museum, and is a Swiss heritage site of national significance.

The Kyburg family 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.