Otto Haab (19 April 1850 – 17 October 1931) was a Swiss ophthalmologist who was a native of Wülflingen, which today is a district in the city of Winterthur.
In 1875, he obtained his doctorate from the University of Zurich, where, as a student, he was an assistant to Karl Joseph Eberth in pathological anatomy.
In 1886, he succeeded Johann Friedrich Horner as professor of ophthalmology at Zurich, a position he held until 1919.
Otto Haab made contributions involving pathological anatomy of the eye, as well as in treatment of eye-related lesions.
His name is associated with several medical eponyms, that include: "Haab's reflex", which is another name for pupillary light reflex, and "Haab's magnet", a powerful magnet used for removing metallic particles from the eye.