Michael Balls (born 1938 in Norwich), CBE, is a British zoologist and professor emeritus of medical cell biology at Nottingham University. He is best known for his work on laboratory animal welfare and alternatives to animal testing.
The third son of Nellie Mary (née Dawson) and Charles Edward Dunbar Balls (18 February 1901 – 31 December 1948), Balls was born in 1938 in Norwich, Norfolk and studied zoology at Oxford University, graduating with a first in 1960. He conducted research for a DPhil from Oxford at the University of Geneva Switzerland between 1961 and 1964. After post-doctoral research at the University of California, Berkeley, CA, and at Reed College, Portland, OR, from 1964 to 1966, he lectured in the School of Biological Sciences at the University of East Anglia, a job that he had got through his friend Ian Gibson. During that time he taught at Eton for a term 
In 1975, he moved to the University of Nottingham Medical School as a senior lecturer in the Department of Human Morphology. Balls became Reader in Medical Cell Biology in 1985 and was promoted to Professor of Medical Cell Biology in 1990. Since 1995, he has been an Emeritus Professor at Nottingham.
Balls became a Trustee of Fund for the Replacement of Animals in Medical Experiments (FRAME) in 1979, and was Chairman of the Trustees from 1981 until his resignation in June 2013. He became Editor of Alternatives to Laboratory Animals (ATLA) in 1983.
He acted as an adviser to the British government during the drafting and passage of the Animals (Scientific Procedures) Act 1986 and, from 1987–1995, was a founder member of the Animal Procedures Committee (which advises the Home Secretary on all matters related to animal experimentation).
In 1993, Balls became the first Head of the European Centre for the Validation of Alternative Methods. He retired from this position in 2002.
Balls has won a number of awards related to his work:
- Marchig Animal Welfare Award – World Animal Protection
1986 (first award)
- Russell & Burch Award – The Humane Society of the United States
1994 Contributions to the advancement of alternative methods
- SmithKline Beecham Laboratory Animal Welfare Prize
1997 Outstanding contributions to the welfare of laboratory animals
- Michael Kay Award – Royal Society for the Prevention of Cruelty to Animals
1999 Recognition of services to European animal welfare
- Origins of the Cameron-Balls Feud
- "ATLA -Alternatives To Laboratory Animals". Federal Institute for Risk Assessment (BfR). Retrieved 4 December 2013.
- "London Gazette Issue 56595 Supplement No.1". London Gazette (London). 15 June 2002. Retrieved 3 December 2013.
- "Ed Balls' father urges review of animal testing laws". Daily Mail (London). 23 July 2007. Retrieved 11 October 2010.