Theobald Ziegler (9 February 1846 – 1 September 1918) was a German philosopher and educator born in Göppingen, Württemberg.
Ziegler studied theology and philosophy at the University of Tübingen, and later was a secondary school teacher in Heilbronn, Winterthur and Baden-Baden. During this time period he also taught classes at Tübinger Stift. In 1882 he became konrektor of a Protestant secondary school in Strasbourg, followed by an appointment as professor of philosophy at the University of Strasbourg (1886).
Among his literary efforts was a biography of David Friedrich Strauss, and a 1900 publication on Friedrich Nietzsche that was based on lectures Ziegler gave in 1897–98. Other significant writings by Ziegler include:
Today, in Frankfurt am Main, the "Theobald-Ziegler-Schule" (primary school) is named in his honor.