Charles Herbert Best (February 27, 1899 - March 31, 1978) was a medical scientist.

He was born in West Pembroke, Maine , USA to Canadian parents.

While a 22-year-old student studying medicine at the University of Toronto, he worked as an assistant to Dr. Frederick Banting and played a vital role in the discovery of the pancreatic hormone insulin, one of the most significant advances in medicine at the time. Upset that the Nobel Prize committee chose to honor John Macleod rather than Best, Banting would share his 1923 Nobel Prize in Medicine with Charles Best.

During World War II Dr. Best was influential in establishing a Canadian program for securing and using dried human blood serum. In his later years Dr. Best would act as adviser to the medical research committee of the United Nations World Health Organization.

In 1967 he was made a Companion of the Order of Canada.

Dr. Best is interred in Mount Pleasant Cemetery, Toronto, Ontario, Canada.