Maximilian Haider (born 23 January 1950 in Freistadt, Austria) is an Austrian physicist.
He studied Physics at the University of Kiel and the Technische Universität Darmstadt, where he received his doctoral degree with a thesis entitled "Design, construction and testing of a corrected electron energy loss spectrometer with large dispersion and a large acceptance angle" (in German: "Entwurf, Bau und Erprobung eines korrigierten Elektronen-Energieverlust-Spektrometers mit grosser Dispersion und grossem Akzeptanzwinkel").
In 1989 he became Group Leader within the Physical Instrumentation Program at the European Molecular Biology Laboratory (EMBL) where he had already performed some experiments during his doctoral studies.
He is honorary professor at the Karlsruhe Institute of Technology (KIT); co-founder, senior advisor and former president of Corrected Electron Optical Systems GmbH (CEOS), a German company that manufactures correction components for electron microscopes.