Netscape Communicator (or Netscape 4) is a discontinued Internet suite produced by Netscape Communications Corporation, and was the fourth major release in the Netscape line of browsers. It was first in beta in 1996 and was released in June 1997. Netscape Communicator addressed the problem of Netscape Navigator 3.x being used as both the name of the suite and the browser contained within it by renaming the suite to Netscape Communicator. It included more groupware features intended to appeal to enterprises.

In February 1998, Netscape announced that Mozilla.org would co-ordinate the development of Netscape Communicator 5 as "a dedicated team within Netscape with an associated Web site that will promote, foster and guide open dialog and development of Netscape's client source code." However, the aging Communicator code proved to be difficult to work with, so it was abandoned. The whole source code of Communicator was re-written by Mozilla, who were then testing it as Mozilla Application Suite. Netscape, now owned by AOL, finally released Communicator's successor Netscape 6 in November 2000, based on Mozilla Application Suite with changes and additions. Minor updates to Communicator continued to be issued, culminating in the release of Netscape Communicator 4.8 in August 2002.