Spirent Communications plc is a British multinational telecommunications testing company headquartered in Crawley, West Sussex, in the United Kingdom.

The company's electronics business grew rapidly during the dot-com boom of the 1990s, with the 1995 purchase of Telecom Analysis Systems (located in Eatontown, New Jersey) and the 1997 purchase of businesses such as Adtech, a digital test equipment concern based in Hawaii[3] and the company was a member of the FTSE 100 index from time to time.

[13] It went on to buy Mu Dynamics, a Sunnyvale company which makes cloud and app testing products such as Blitz,[14] and Metrico Wireless, a company involved in mobile device performance analytics for wireless service providers, OEMs and corporate enterprises based in Frederick, Maryland, in 2012.

Radvision a company based in Tel Aviv, Israel, offers development and test suites for voice and video over IP communications.

[19] In March 2021, Spirent acquired octoScope, a company based in Littleton, Massachusetts that offers solutions for automated Wi-Fi and 5G testing in emulated real-world environments.