Willem Johannes Maria (Pim) Levelt (born 17 May 1938 in Amsterdam) is a Dutch psycholinguist.

He developed a comprehensive theory of the cognitive processes involved in the act of speaking, including the significance of the "mental lexicon".

Levelt was the founding director of the Max Planck Institute for Psycholinguistics in Nijmegen.

In 1965, he received his doctorate (cum laude) with John P. van de Geer with a thesis on binocular rivalry.

From 1976, Levelt headed the newly founded project group for psycholinguistics at the Max Planck Society in Nijmegen.

In an analogy to computer language, Levelt distinguishes between memory and process components.