Sir Michael John Berridge FRS FMedSci FBPhS (22 October 1938 – 13 February 2020) was a British physiologist and biochemist. He was known for his work on cell signaling, in particular the discovery that inositol trisphosphate acts as a second messenger, linking events at the plasma membrane with the release of calcium ions (Ca²⁺) within the cell.

Berridge was born in Gatooma (now Kadoma, Zimbabwe) in Southern Rhodesia (now Zimbabwe). His high school biology teacher convinced him and his parents that he should pursue tertiary education, and he entered the newly founded University of Rhodesia and Nyasaland (now University of Zimbabwe), earning his Bsc in zoology and chemistry in 1960.

He became interested in insect physiology after helping with his physiology professor's research on tsetse flies, and went to the United Kingdom to study with Vincent Wigglesworth, regarded as the father of insect physiology, at the Department of Zoology of the University of Cambridge. Berridge became a member at the Gonville and Caius College, where Wigglesworth was a fellow, and obtained his PhD in 1965.

Initially intending to return to Southern Rhodesia (now Zimbabwe) after his PhD, Berridge's plan was thwarted by the Rhodesian Bush War. He migrated to the United States instead, joining the Department of Biology of the University of Virginia as a postdoctoral fellow. A year later, he moved to the Developmental Biology Center of Case Western Reserve University. He became a research associate under Bodil Schmidt-Nielsen at the Department of Biology of the same university in 1967.

In 1969, John Treherne invited Berridge to return to the University of Cambridge and join the new Unit of Invertebrate Chemistry and Physiology that he was setting up in the Department of Zoology. He first joined as a senior scientific officer, and was promoted to principal scientific officer in 1972. He became a senior principal scientific officer at the Unit of Insect Neurophysiology and Pharmacology, also at the University of Cambridge, in 1978.

In 1990, Berridge joined the Babraham Institute as the Deputy Chief Scientific Officer of the Laboratory of Molecular Signalling, before serving as the Head of Signalling in 1996 until retiring in 2003. After retirement, Berridge was appointed as Babraham's first emeritus Babraham Fellow.

Berridge was a fellow of the Trinity College of the University of Cambridge from 1972 until his death.

Berridge maintained an online textbook on cell signalling, now hosted by Portland Press under the Biochemical Society.