Theodore "Ted" Sider is an American philosopher specializing in metaphysics and philosophy of language. He is Professor of Philosophy at Rutgers University.
Since earning his Ph.D. from the University of Massachusetts Amherst in 1993, Sider has taught at the University of Rochester, Syracuse University, New York University, Cornell University, and Rutgers University from 2002-2007 and, again, since 2015. Sider has published three books and some four dozen papers. He has also edited a textbook in metaphysics with John Hawthorne and Dean Zimmerman.
Sider was the recipient of the 2003 APA Book Prize for his book, Four-Dimensionalism: An Ontology of Persistence and Time.
Sider is one of the leading figures in contemporary metaphysics. He gave the John Locke Lectures at Oxford University in 2016.