Sir David Bates, FRS (born 18 November 1916) was an Irish mathematician and physicist.
Born in Omagh, County Tyrone, he moved to Belfast with his family in 1925, attending the Royal Belfast Academical Institution. He enrolled with the Queen's University of Belfast in 1934. In 1939 he became a research student under Harrie Massey.
During the Second World War he developed methods of protecting ships from magnetically activated mines.
Working at University College from 1945 until 1951, he then returned once more to the Queen's University of Belfast. He remained there until his retirement in 1982.
His contributions to science include seminal works on atmospheric physics, molecular physics and the chemistry of interstellar clouds. He was knighted in 1978 for his services to science, was a Fellow of the Royal Society and vice-president of the Royal Irish Academy. In 1970 he won the Hughes Medal.
The Sir David Bates Medal, created in his honour, is awarded yearly for outstanding contributions to planetary and solar system science.