The Siemon Company is an American telecommunications company founded in 1903 that provides IT infrastructure hardware and services for data centers, local area networks (LANs) and intelligent buildings.

The Siemon Company offers copper and optical fiber cabling systems, cabinets, racks, cable management, data center power and cooling systems.

[1] In 1906, The Siemon Company began manufacturing of a three-pole connecting block for AT&T.

Carl Siemon manufactured a durable plastic version identical to the AT&T block and became a supplier for AT&T and the later "Baby Bells."

In 2016, Siemon acquires Gigaduct Fiber Containment System for data centers.