David Keilin FRS[1] (21 March 1887 – 27 February 1963) was a British Jewish scientist focusing mainly on entomology.

[4] He did not attend school until age ten due to ill health and asthma.

Keilin became research assistant to George Nuttall, first Quick Professor of Biology at the University of Cambridge, in 1915, and spent the rest of his career there, succeeding Nuttall as Quick Professor and director of the Molteno Institute in 1931.

He published thirty-nine papers between 1914 and 1923 on the reproduction of lice, the life-cycle of the horse bot-fly, the respiratory adaptations in fly larvae, and other subjects.

The Keilin Memorial Lecture[7] of the Biochemical Society began in 1964 in his memory, and recipients and the subject of their talk is selected by a committee reflecting Keilin's interests in bioenergetics, electron transfer and mitochondrial biology.