3Com Corporation was an American digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others. Bill Krause joined as President in 1981. Metcalfe explained the name 3Com was a contraction of "Computer Communication Compatibility", with its focus on Ethernet technology that he had co-invented, which enabled the networking of computers.

3Com provided network interface controller and switches, routers, wireless access points and controllers, IP voice systems, and intrusion prevention systems. The company was based in Santa Clara, California. From its 2007 acquisition of 100 percent ownership of H3C Technologies Co., Limited (H3C) —initially a joint venture with China-based Huawei Technologies—3Com achieved a market presence in China, and a significant networking market share in Europe, Asia, and the Americas. 3Com products were sold under the brands 3Com, H3C, and TippingPoint.

On April 12, 2010, Hewlett-Packard completed the acquisition of 3Com, and it no longer exists as a separate entity. 3Com's products, support, and technologies were eventually merged into HPE's Aruba Networks business unit following HP's acquisition of Aruba in 2015 and subsequent split into HPE later that same year.