Newsqueak is a concurrent programming language for writing application software for windowing systems. It was designed at Bell Labs by Rob Pike in the late 1980s.
Newsqueak's syntax and semantics are influenced by the C language, but its approach to concurrency was inspired by C. A. R. Hoare's communicating sequential processes (CSP). However, in Newsqueak, channels are first-class objects, with dynamic process creation and dynamic channel creation.
Newsqueak was developed from an earlier, smaller, language, called Squeak (not to be confused with the Smalltalk implementation Squeak). It was developed by Luca Cardelli and Rob Pike as a language for implementing graphical user interfaces.
The ideas present in Newsqueak were further developed in the programming languages Alef, Limbo, and Go.