**Peter Manfred Gruber** (28 August 1941, Klagenfurt – 7 March 2017, Vienna) was an Austrian mathematician working in geometric number theory^{[1]} as well as in convex and discrete geometry.^{[2]}^{[3]}

Gruber obtained his PhD at the University of Vienna in 1966, under the supervision of Nikolaus Hofreiter.^{[4]} From 1971, he was Professor at the University of Linz, and from 1976, at the TU Wien.^{[1]} He was a member of the Austrian Academy of Sciences,^{[1]}^{[5]} a foreign member of the Russian Academy of Sciences,^{[1]}^{[6]} and a corresponding member of the Bavarian Academy of Sciences and Humanities.^{[1]}^{[7]}

His past doctoral students include Monika Ludwig.^{[4]}

- Gruber, P.M. (2007).
*Convex and Discrete Geometry*. Berlin: Springer-Verlag.CS1 maint: ref=harv (link) - Gruber, P.M.; Lekkerkerker, C.G. (1987).
*Geometry of Numbers*. Amsterdam: North-Holland.CS1 maint: ref=harv (link)

- 1967: Prize of the Austrian Mathematical Society
- 1978, 1980 and 1982: Chairman of the Austrian Mathematical Society
- 1991: Full member of the Austrian Academy of Sciences (Corresponding member since 1988)
- 1996: Medal of the Union of Czech Mathematicians and Physicists
- 2001: Austrian Cross of Honour for Science and Art, 1st class
^{[8]} - 2001: Medal of the mathematical and physical faculty of Charles University in Prague
- 2003: Foreign member of the Russian Academy of Sciences
- 2008: Grand Silver Medal for Services to the Republic of Austria
^{[9]} - 2013: Fellow of the American Mathematical Society, for "contributions to the geometry of numbers and to convex and discrete geometry".
^{[2]} - Honorary doctorates from the Universities of Siegen, Turin and Salzburg
- Member of the Academies of Sciences in Messina and Modena
- Corresponding member of the Bavarian Academy of Sciences