Sir Theodore Morris Sugden FRS, (31 December 1919 – 3 January 1984) was a British chemist who specialised in combustion research.

After attending Sowerby Bridge and District Secondary School he gained an open scholarship to Jesus College, Cambridge in 1938, where he read chemistry and was awarded a First in 1940.

That year he began research under physicist W C Price on the measurement of precise ionization potentials of molecules.

He graduated from Oxford in Botany in 1975, and later gained a doctorate in tropical rainforest ecology.

He undertook an expedition to the Serranía de Macuira in northern Colombia, publishing a checklist to the plants of this area along with Enrique Forero.