Roger Balian (b. Jan 18 1933) is a French physicist who has worked on quantum thermodynamics and theory of measurement . Balian is a membre of French Académie des sciences (Academy of Sciences). His important work includes the Balian-Low theorem .

Balian wrote the influential book From Microphysics to Macrophysics (ISBN 3-540-53266-8), which is based on a course of statistical physics he taught at the École Polytechnique.