Larry Fleinhardt is a fictional character in the television show Numb3rs, played by Peter MacNicol.

Dr. Lawrence Fleinhardt is a professor of physics at CalSci (a university based on Caltech and located in Los Angeles in the Numb3rs universe) and best friend and colleague of Charlie Eppes. He is portrayed as a brilliant theoretical physicist and cosmologist, who researches supersymmetry, string theory, 11-dimensional supergravity theory, doubly-special relativity, black holes, and gravitational waves, using LIGO to check predictions on quantum corrections. He may have even found a way to express Calabi-Yau manifolds in a way that goes beyond a non-vanishing harmonic spinor and, independent of Charlie, published a work of genius entitled Zero Point Energy and Quantum Cosmology, which could provide insight into the cosmological constant problem (episode 3x4,The Mole).