-	Tekfen Şirketler Grubu
-	Tekfen Tower
-	Tekfen İnşaat ve Tesisat A.Ş.
	Tekfen Mühendislik A.Ş.
-	Tekfen Ceyhan Çelik Fabrikası
-	Tekfen Emlak Gelistirme
-	Toros Gübre ve Kimya Endüstrisi A.Ş.
-	TAYSEB - Toros Adana Yumurtalık Serbest Bölgesi
-	Tekfen Sigorta Aracılık Hizmetleri A.Ş.
-	Azfen
-	Hallesche Mitteldeutsche Bau AG (HMB)
-	Akmerkez
-	Antalya Stüdyoları A.Ş.
-	The American Society of Mechanical Engineers (ASME)
-	The National Board of Boiler and Pressure Vessel Inspectors
-	Tubular Exchanger Manufacturers Association, Inc. (TEMA)
-	The American Society For Nondestructive Testing (ASNT)
-	American Society for Testing and Materials (ASTM)
-	American Welding Society (AWS)
-	American National Standards Institute (ANSI)
-	American Petroleum Institute (API)
-	NACE International
-	British Standards (BSI)
-	National Institute of Standards and Technology (NIST)
-	Welding Research Council (WRC)
-	Material Properties Council (MPC)
-	Pressure Vessel Research Council (PVRC)
-	DIN Deutsches Institut für Normung e. V.
-	European Committee for Standardization (CEN)
-	International Organization for Standardization (ISO)
-	Pressure Equipment Directive (PED 2014/68/EU)
-	ADR - International Carriage of Dangerous Goods by Road
-	Equipment intended for use in Potentially Explosive Atmospheres (ATEX) Directive 2014/34/EU