Peter Karl Henrici (13 September 1923 – 13 March 1987) was a Swiss mathematician best known for his contributions to the field of numerical analysis.

After World War II he transferred to ETH Zürich where he received a diploma in electrical engineering (1948) and a doctorate in mathematics with Eduard Stiefel as his advisor (1952).

In 1951 he moved to the United States and worked on a joint contract with American University and the National Bureau of Standards.

In 1962 he returned to ETH Zürich as a professor, a position he kept for the rest of his life, though he also held a part-time appointment as William R. Kenan, Jr.

[1][2] An internationally recognized numerical analyst, who published 11 books and more than 80 research papers, Henrici was also a gifted pianist and a highly regarded teacher.