Keith Sedgwick Donnellan (/ˈdɒnələn/; June 25, 1931 – February 20, 2015) was an American philosopher and Professor of Philosophy (later Professor Emeritus) at the University of California, Los Angeles. Donnellan contributed to the philosophy of language, notably to the analysis of proper names and definite descriptions. He criticized Bertrand Russell's theory of definite descriptions for overlooking the distinction between referential and attributive use of definite descriptions.