Cisco Systems was founded in December 1984 by Leonard Bosack and Sandy Lerner, two Stanford University computer scientists who had been instrumental in connecting computers at Stanford. They pioneered the concept of a local area network (LAN) being used to connect geographically disparate computers over a multiprotocol router system. By the time the company went public in 1990, Cisco had a market capitalization of $224 million; by the end of the dot-com bubble in the year 2000, this had increased to $500 billion. As of December 2021, Cisco has a market cap of around $267 billion.

Cisco stock (CSCO) was added to the Dow Jones Industrial Average on June 8, 2009, and is also included in the S&P 500 Index, the Russell 1000 Index, NASDAQ-100 Index and the Russell 1000 Growth Stock Index.

In 2021, Fortune ranked Cisco number one for the second year on their annual list of the 100 Best Companies to Work For based on employee satisfaction surveying. LinkedIn and Glassdoor also ranked Cisco as a top place to work in 2021 and recent years.