Waldburg-Zeil was a County and later Principality within Holy Roman Empire, ruled by the House of Waldburg, located in southeastern Baden-Württemberg, Germany, located around Schloss Zeil, near Leutkirch im Allgäu.

Originally ruled by Truchesses (stewards), Waldburg-Zeil was elevated to a County in 1628, and a Principality in 1803 shortly before being mediatised to Württemberg in 1806.

The present prince is Erich, Fürst von Waldburg zu Zeil und Trauchburg (born 1962), the only son of Georg, Prince von Waldburg zu Zeil und Trauchburg (1928-2015) and Princess Marie Gabrielle of Bavaria (b.

As Erich has five daughters, his heir presumptive is his first cousin, Count Clemens von Waldburg-Zeil (b.

In 1779 a side branch of the Counts of Waldburg-Zeil inherited the sovereign county of Lustenau by marriage.