Alexander Levitzki (Hebrew: אלכסנדר לויצקי; born 13 August 1940) is an Israeli biochemist who is a professor of biochemistry at the Hebrew University of Jerusalem.

Levitzki was born in 1940 in Palestine.

He received his Ph.D. in biochemistry and biophysics from the Hebrew University of Jerusalem and the Weizmann Institute of Science, in 1968.

In 1970, Levitzki became a senior scientist at the Department of Biophysics, Weizmann Institute of Science.

In 1974, he became an associate professor at the same institute.

In 1974, he became an associate professor at the Hebrew University of Jerusalem.

In 1976, he was promoted to professor of biochemistry at the Hebrew University of Jerusalem.

Levitzki demonstrated (1993) that such an inhibitor of Bcr-Abl kinase induces death of chronic myeloid leukemia (CML) cells.

This work led to the development of Gleevec by Novartis (1996) that is currently used, with great success, for therapy of patients afflicted by this disease.

In 2006 his research team developed a method for inducing brain tumor cells to "commit suicide".

In 1990, he was awarded the Israel Prize, in life sciences (following in the footsteps of his father, Jacob Levitzki, who had received the prize, for exact sciences, in 1953).

In 2005, he was awarded the Wolf Prize in Medicine for "pioneering signal transduction therapy and for developing tyrosine kinase inhibitors as effective agents against cancer and a range of other diseases".