Geoffrey K. Pullum is Professor Emeritus of General Linguistics at the University of Edinburgh and affiliate faculty at George Mason University, Fairfax, Virginia. He has worked on a broad array of topics in theoretical linguistics, but has a special interest in the grammar of Standard English and in popular misconceptions of it.

Though born in Scotland, he was raised in England. His first job was as a professional rock musicican (piano, organ, and occasionally guitar): he worked with Pete Gage to found the Ram Jam Band. After five years as a musician he earned a B.A. in Language with First Class Honours at the University of York, spent a year as a research student at King's College, Cambridge, and earned the Ph.D. in General Linguistics at the University of London. In 1980 he emigrated to the USA and later became an American citizen.

He has served on the faculty at University College London (1974–1980); the University of California, Santa Cruz (1981–2007); and the University of Edinburgh (2007–2020), and has also held visiting professorships at the University of Washington, Stanford University, and Brown University.

He has held fellowships at the Center for Advanced Study in the Behavioral Sciences and at the Radcliffe Institute for Advanced Study at Harvard, and has been elected to the American Academy of Arts and Sciences, the British Academy, and the Academia Europaea.

His roughly 300 publications are highly diverse: technical works on syntactic theory, a handbook on phonetic transcription (Phonetic Symbol Guide, 2nd edition 1996, translated into Japanese in 2003), a collection of satirical essays about the study of language (The Great Eskimo Vocabulary Hoax, 1991), a collection of humorous articles from Language Log (Far from the Madding Gerund, with Mark Liberman, 2006), a short popular book called Linguistics: Why It Matters (Polity Press, 2018, translated into Chinese in 2022), and a wide variety of other items. His best-known work is The Cambridge Grammar of the English Language (by Rodney Huddleston and Geoffrey K. Pullum et al., Cambridge University Press, 2002), which is a comprehensive description of the linguistic structure of international standard English that was awarded the the Linguistic Society of America's Leonard Bloomfield Book Award in January 2004. A textbook based on The Cambridge Grammar was published by CUP in 2005 (A Student's Introduction to English Grammar, with Rodney Huddleston); it appeared in a revised second edition (with Huddleston and also Brett Reynolds) in 2022.