Nextel Communications, Inc. was an American wireless service operator that merged with and ceased to exist as a subsidiary of Sprint Corporation, which would later be bought by T-Mobile US and folded into that company. Nextel in Brazil, and formerly in Argentina, Chile, Peru, the Philippines, and Mexico, is part of NII Holdings, a stand-alone, publicly traded company not owned by Sprint Corporation.

Nextel Communications traces its roots to the 1987 foundation of FleetCall by Morgan O'Brien, Brian McAuley, Chris Rogers, and Peter Reinheimer. FleetCall changed its name to Nextel Communications, Inc. in 1993. Nextel provided digital, wireless communications services, originally focusing on the fleet and dispatch customers, but later marketed to all potential wireless customers. Nextel's network operated in the 800-MHz Specialized Mobile Radio band and used iDEN technology developed by Motorola. Nextel's iDEN network offered a then unique push-to-talk "walkie-talkie" feature in addition to direct-dialed voice calls. Nextel was one of the first providers in the United States to offer a national digital cellular coverage footprint.

Prior to merging with Sprint Corporation in 2005, Nextel Communications, Inc. was a publicly traded company. Shares traded on the NASDAQ under the ticker symbol NXTL. Nextel was headquartered in Reston, Virginia, United States.

At the time of its 2005 merger with Sprint Corp., Nextel had over twenty million subscribers in the United States and served 198 of the top 200 markets. Nextel Communications, Inc. offered postpaid services under the Nextel brand and prepaid services under the Boost Mobile brand.

In late 2010, Sprint Nextel announced plans to decommission the Nextel iDEN network; on May 30, 2012, Sprint Nextel announced that it would shut down the Nextel network as early as June 2013. The Nextel network was officially shut down at 12:01am on June 30, 2013, and Sprint began the process of deploying LTE equipment on the 800 MHz spectrum formerly used by the iDEN network.

Before the acquisition by T-Mobile US, Sprint Corporation continued to offer pre-paid services under the Boost Mobile brand and also offered push-to-talk services as Sprint Direct Connect using CDMA equipment.

Telecommunication lawyers Morgan E. O'Brien and Chris Rogers and investment bankers Brian McAuley and Peter Reinheimer founded FleetCall in 1987. FleetCall changed its name to Nextel Communications in 1993. In 1995, wireless industry pioneer Craig McCaw became a significant investor in the company. Other early investors and employees include Mark Warner, now a United States Senator from Virginia, and Jack Markell, the former Governor of Delaware.

The founders chose the name "FleetCall" because the company's network used the 800 MHz Specialized Mobile Radio frequencies designated by the Federal Communications Commission for use in fleet dispatch. The core of the business model was to buy these fleet dispatch frequencies from existing operators at a substantial discount when compared to the cost for the equivalent bandwidth available via auction from the Federal Communications Commission. These "non-cellular" frequencies were made usable for a consumer and business wireless voice telephone service with the iDEN technology developed by Motorola, which some observers at the time said would not be practical. Initially, FleetCall did not want to include the push to talk feature in their phones, but the FCC required it as the initial frequencies were licensed for dispatch use. Later, Nextel would use the push-to-talk feature as a key marketing advantage.