Björn Engquist (also Bjorn Engquist; born 2 June 1945 in Stockholm) has been a leading contributor in the areas of multiscale modeling and scientific computing, and a productive educator of applied mathematicians.

In 2001, he moved to Princeton University as the Michael Henry Stater University Professor of Mathematics and served as the director of the Program in Applied and Computational Mathematics.

His research field is computational and applied mathematics and numerical methods for differential equations with applications to multi-scale modeling, electromagnetism, and fluid mechanics.

Engquist has authored more than 100 scientific publications and advised 31 PhD students.

He is a recipient of numerous distinctions and awards: a member of the American Academy of Arts & Sciences, a member of the Royal Swedish Academy of Sciences and the Royal Swedish Academy of Engineering Sciences, and an invited speaker at the International Congress of Mathematicians (1982 and 1998[1]), European Congress of Mathematics (1992), and European Congress of Fluid Mechanics (1991).