Peter Walter (born 5 December 1954) is a German-American molecular biologist and biochemist and Professor at the University of California, San Francisco. 

Walter earned a B.S. degree in chemistry from the Free University of Berlin, an M.S. degree in organic chemistry from Vanderbilt University, and a Ph.D. in biochemistry from the Rockefeller University.

He is currently a Professor and former Chair of the Department of Biochemistry and Biophysics at the University of California, San Francisco (UCSF). 

Walter is an Investigator of the Howard Hughes Medical Institute and a member of the National Academy of Sciences. Dr. Walter has put together a select group of world-renowned experts in neuroscience, cell biology, molecular biology, microbiology and RNA biology to make Altos Labs a reality.