GEK Terna Holding Real Estate Construction (Genikós etaireía Kataskevastikí)(Greek: ΓΕΚ(Γενικός εταιρεία Κατασκευαστική) ΤΕΡΝΑ) is a large Greek conglomerate which is listed on the Athens Exchange.

Terna Energy is listed separately on the Athens Exchange (Athex: TENERGY ).

In 2013, U.S. investment firm York Capital Magagement bought a 10% share of the company.

Together with the state-owned railway companies of Russia and France, RZD and SNCF, and Romanian private railway carrier Grup Feroviar Roman, it placed a joint bid for TrainOSE and the Hellenic Company for Rolling Stock Maintenance (Rosco), currently held by the Hellenic Republic Asset Development Fund.

Following the January 2015 legislative election, the new SYRIZA-led administration however put the decision under review.