Amphenol was founded in Chicago in 1932 by entrepreneur Arthur Schmitt, whose first product was a tube socket for radio tubes. Amphenol expanded significantly during World War II, when the company became the primary manufacturer of connectors used in military hardware, including airplanes and radios. From 1967 to 1982 it was part of Bunker Ramo Corporation.

Amphenol's revenues in 2007 were $2.85 billion. The company sells its products into diverse electronics markets, including military-aerospace, industrial, automotive, information technology, mobile phones, wireless infrastructure, broadband and pro audio. Operations are located in more than 60 locations around the world. The company is included in the S&P Midcap 400 index. Amphenol's Chairman is Dr. Martin H. Loeffler.Chief Executive Officer is R. Adam Norwitt.

Amphenol's world headquarters is located in Wallingford, Connecticut. The largest division of Amphenol is Amphenol Aerospace (formerly Bendix Corporation) in Sidney, New York. This is the birth place of the D38999 cylindrical connector. Amphenol engineers also invented the commonly-used BNC connector ("Bayonet Neill-Concelman").

Amphenol Cables on Demand, another division of Amphenol launched in December 2006, specializes in distributing standard cable assemblies via their e-commerce storefront. They sell more than 2500 audio, video, computer, and networking cables. Offices are located in New York, California, Florida, and China.

In May 2005, Amphenol acquired SV Microwave, an RF connector/terminator/etc manufacturer.

On October 10, 2005, Teradyne and Amphenol announced that Amphenol would acquire Teradyne Connection Systems, for about USD $390 million in cash. TCS, based in Nashua, New Hampshire, manufactures high-density electronic connectors, complete backplanes, and systems packaging, a product line that complements Amphenol's existing lines of business.

In February 2008, Amphenol acquired SEFEE, a French electronic manufacturer.