Szolem Mandelbrojt (1899 – 1983) was a French mathematician, from a Polish-Lithuanian Jewish background. He worked mainly in classical analysis; he was a student of Jacques Hadamard, and became Hadamard's successor as Professor at the Collège de France.

He was an early member of the Bourbaki group, taking part in some of its initial gatherings. In fact his direction was very different, as his publications show, with an interest in Dirichlet series, lacunary series , entire functions and other major topics in complex analysis and harmonic analysis. In fact he is more accurately described as a follower of G. H. Hardy, and can be placed in the group containing Norbert Wiener and Torsten Carleman who were moderate modernisers of classical Fourier analysis. Agmon Shmuel was one of his students.

During World War II he was in the USA, in Houston at the Rice Institute from 1940, being one of many French scientists helped by the programme of Louis Rapkine (1904-1948) after the fall of France in June 1940.

Benoît Mandelbrot is his nephew.