Otto Fridolinus Fritzsche also Otto Fridolin Fritzsche (September 23, 1812 in Dobrilugk – March 9, 1896 in Zurich) was a German Protestant theologian. He was born to a minister named Christian Friedrich Fritzsche (1776–1850).
He studied at the University of Halle, where in 1836 he obtained his habilitation. In 1837 he became an associate professor of theology at the University of Zurich. In 1842 he became a titular professor, followed by a full professorship in 1860. At the same time, he held from 1844 until his death, the post of chief librarian at the cantonal library.
His writings were mainly in the fields of biblical exegesis and church history. His major works include his Apocrypha of the Old Testament (1871).