Frederick George Donnan (6 September 1870 – 16 December 1956) was a Ceylonese-born British chemist who is known for the Gibbs–Donnan effect describing ionic transport in cells.

[7] He studied at Queen's College, Belfast gaining a Bachelor of Arts degree in 1894, then at the University of Leipzig with Wilhelm Ostwald, resulting in a PhD in 1896, followed by research with J. H. van't Hoff.

[1] Donnan's 1911 paper[10] on membrane equilibrium was important for leather and gelatin technology, but even more so for understanding the transport of materials between living cells and their surroundings.

[8][11] It was on this so-called Donnan equilibrium that he frequently was asked to lecture across Europe and America,[1] and is largely the only scientific research for which he is remembered today.

Just before World War II, Donnan was active in helping European refugees wanting to flee from the Nazis.