Sydney MacDonald Lamb (born May 4, 1929 in Denver, Colorado) is an American linguist and professor at Rice University, whose stratificational grammar is a significant alternative theory to Chomsky's transformational grammar. He has specialized in Neurocognitive Linguistics and a stratificational approach to language understanding.
Lamb earned his Ph.D. from the University of California, Berkeley in 1958 and taught there from 1956 to 1964. His dissertation was a grammar of the Uto-Aztecan language Mono, under the direction of Mary Haas and Murray B. Emeneau. In 1964, he began teaching at Yale University before joining the Semionics Associates in Berkeley, California in 1977. Lamb did research in North American Indian languages specifically in those geographically centered on California. His contributions have been wide-ranging, including those to historical linguistics, computational linguistics, and the theory of linguistic structure. His work led to innovative designs of content-addressable memory hardware for microcomputers.