* Roland Clift Developer of Life cycle assessment and broadcaster on environmental issues
* John Coulson (1910–1990) Co-writer of classic UK textbooks
* M. B. Donald (1897 - 1978) Fourth Ramsay professor of Chemical engineering at University College London. Former honorary secretary and vice-president of IChemE, Institution's Donald medal named after him. 
* Sir Arthur Duckham (1879–1932) First President of the IChemE
* Ian Fells Noted energy expert and popular science broadcaster
* Trevor Kletz (1922-2013) Noted safety expert
* Ashok Kumar (1956–2010) UK Member of Parliament
* Frank Lees (1931–1999) author of major safety encyclopaedia
* Bodo Linnhoff His 1979 PhD thesis led to Pinch Technology which has enabled companies to save large amounts of energy
* K. B. Quinan (1878–1958) An American who, according to Lloyd George "did more than any other single individual to win the (First World) War" 
* Jack Richardson (1929–2011) Co-writer of classic UK textbooks
* P. N. Rowe (1919-2014) Fifth Ramsay professor of chemical engineering at University College London. He was president of the Institution between 1981 and 1982.
* Meredith Thring (1915–2006) prolific inventor, futurologist and early proponent of sustainability