Sir William Alexander Denny KNZM (born 5 August 1943) is a New Zealand medicinal chemist, noted for his work investigating drugs for the treatment of cancer.

[8] In 1995, he was awarded the society's Rutherford Medal, alongside the Auckland Cancer Research Laboratory, for innovation in the development of new anti-cancer drugs.

[9] In the 2003 Queen's Birthday Honours, Denny was appointed an Officer of the New Zealand Order of Merit, for services to cancer research.

[10] He was promoted to Knight Companion of the New Zealand Order of Merit, for services to medical research, in the 2021 Queen's Birthday Honours.

[11] Denny was inducted into the American Chemical Society Division of Medicinal Chemistry Hall of Fame in 2016.