Brian J. Druker, M.D. (born April 30, 1955) is a physician-scientist and JELD-WEN Chair of Leukemia Research at Oregon Health & Science University (OHSU) in Portland, Oregon. In 2025, he was named the inaugural president of the newly independent Knight Cancer Group, a self-governing entity formed by the Oregon Health & Science University's Knight Cancer Institute following a record $2 billion gift from Phil and Penny Knight. He previously served as chief executive officer and director of OHSU's Knight Cancer Institute, as well as Associate Dean for Oncology in the OHSU School of Medicine.

Druker helped develop imatinib (Gleevec), the first medication that specifically targets cancer cells, for the treatment of chronic myeloid leukemia (CML). In 2001, Gleevec gained FDA approval in record time and landed on the cover of Time magazine. Druker’s work launched the era of precision cancer medicine, setting the stage for future discoveries in the quest to end cancer.

He is the recipient of the 2009 Lasker-DeBakey Clinical Medical Research Award, the 2012 Japan Prize in Healthcare and Medical Technology, the 2013 Albany Medical Center Prize in Medicine and Biomedical Research, and the 2019 Sjöberg Prize, among others. He has been called "Oregon's best-known scientist".

Druker earned both his B.A. degree in chemistry and M.D. degree from the University of California, San Diego. He completed his internship and residency in internal medicine at Barnes Hospital, Washington University School of Medicine in St. Louis from 1981 to 1984.

Druker was a fellow in medical oncology at Dana–Farber Cancer Institute at Harvard Medical School from 1984 to 1987. He began working at Oregon Health & Science University (OHSU) in 1993.

Druker's research is focused on translating the knowledge of the molecular pathogenesis of cancer into specific therapies and investigating the optimal use of these molecularly targeted agents. He performed preclinical studies that led to the development of imatinib (Gleevec) for chronic myeloid leukemia (CML) and then spearheaded the highly successful clinical trials of imatinib, which led to FDA approval of the drug in record time. This work changed the life expectancy of patients with CML from an average of 3 to 5 years to a 89% five-year survival, and has resulted in a paradigm-shift in cancer treatment from non-specific chemotherapy to highly targeted therapeutic agents. Druker has been widely recognized for his work in developing Gleevec, but has been publicly critical of the drug's high price for patients.

Druker also helped lead a national clinical trial to find effective treatments for acute myeloid leukemia (AML). The Beat AML clinical trial, sponsored by the Leukemia & Lymphoma Society (LLS), is a joint effort by medical centers, drug makers and the Food and Drug Administration.

In May 2007, he became director of the OHSU Cancer Institute—renamed the Knight Cancer Institute in October 2008 following a $100 million donation from Nike co-founder Phil Knight.