Fayyazuddin or Fayyaz Uddin, HI (Urdu: ???? ?????) (born 10 November 1930), is a Pakistani theoretical physicist and an emeritus professor of Theoretical and Mathematical Physics at National Centre for Physics and Quaid-e-Azam University, Islamabad.
He is a senior scientist at the National Center for Physics where his research is engaged to the fields of quantum mechanics, particle physics, and meson physics.
He is a brother of physicist Riazuddin and the student of Abdus Salam.
Along with Riazuddin, he has published numerous physics papers and has co-authored Quantum Mechanics by Fayyazuddin and Riazuddin which was published in 2000.