Alec Marantz (born January 31, 1959) is an American linguist and researcher in the fields of syntax, morphology, and neurolinguistics.

Until 2007, he was Kenan Sahin Distinguished Professor of Linguistics at Massachusetts Institute of Technology, and Research Director of KIT/MIT MEG Joint Research Lab.

Since the 1980s Marantz has made significant contributions to syntactic theory, especially regarding the structural representation of syntactic arguments, and the semantic and morphological implications of this representation.

In the early 1990s Marantz proposed (together with Morris Halle) a theory of architecture of grammar known as Distributed Morphology.

More recently, he has been using magnetoencephalography (MEG) to study human language processing, particularly morphology and the mental lexicon.