Open Fiber (formerly Enel Open Fiber S.p.A.) is an Italian company that operates wholesale in the Italian market of FTTH network infrastructure.

The company was founded in December 2015, aiming to create, manage, and maintain a high-speed fiber optic FTTH network infrastructure covering the entire Italian geographical area.

At its inception, Enel Open Fiber was wholly owned by Enel.

In 2017, CDP Equity (a company belonging to Cassa Depositi e Prestiti) acquired a 50% stake from Enel, and the company changed its name to Open Fiber. In 2022, Enel sold its 50% stake, which was acquired 40% by Macquarie Asset Management and 10% by CDP Equity, which reached a 60% stake in the company.

Open Fiber, operating solely in the wholesale market, does not provide services directly to end customers but makes its infrastructure available to interested partner operators.