Companies where O.W.T.U. is the Recognized Majority Union (RMU)
Energy
- Petrotrin (Petroleum Company of Trinidad & Tobago)
- Trinmar (Petrotrin Trinmar Operations)
- RAMCO Industries Ltd.
- NATPET
Petro Chemicals
- YARA (Yara Trinidad Ltd.)
- NP (National Petroleum Market Co. Ltd.)
- ANSA McAl Chemical Ltd.
- RAMCO Industries Ltd.
- NATPET
Electricity
- T&TEC (Trinidad & Tobago Electricity Commission)
- Powergen (Power Generation Company of Trinidad & Tobago)
Education Services
- UWI (University of the West Indies St Augustine)
- NTA (National Training Agency)
Hotel
- Blue Heaven - Tobago
- Turtle Beach - Tobago
- Crown Point Beach Hotel - Tobago
Food Processing
- National Canners Ltd.
- Universal Foods Ltd.
- Associated Brands Ltd.
- Flavorite Foods Limited
- Nestlé (Nestle Trinidad & Tobago Ltd.)
Catering
- Food Catering Services Ltd.
Manufacturing
- Unilever Caribbean Ltd.
- Tye Manufacturing Co. Ltd.
Heavy Industry
- TCL (Trinidad Cement Ltd.)
- TAP (Trinidad Aggregate Products Ltd.)
- Readymix Trinidad
Construction
- Damus Ltd.
- Carillion (Carillion Caribbean Ltd.)
Energy Services Industries
- Damus Ltd.
- Caribbean Inspection & Metallurgical Services Ltd.
- Lennox Pettroleum Services Ltd.
- Well Services Ltd.
- Miller Group of Companies
- Offshore Atlantic
- Gulf Marine Services Ltd.
- Coastal Marine
- Global Santa Fe South america L.L.C
- Bristow Caribbean Ltd
- National Helicopter Services Ltd.
- Schlumberger Trinidad Incorporation
- Oilbelt Services Ltd.
- Ventrin Petroleum Co. Ltd.
- Nathan Petroleum Services Co. Ltd.
- Svitzer Marine Trinidad Ltd.
- Rahamut Service Stations
Packaging & Distribution Services
- TCL Packaging Ltd.
- CPI (Caribbean Packaging Industries Ltd.)
- T Geddes Grant Ltd.
Service Industries
- Tobago Dive Experience
- Tobago Taxi Cab Co-Operative Society
Financial Services
- TECU
- Antilles Credit Union
- Zenith Credit Union
- Palo Seco Credit Union
- Mount Pleasant Credit Union (Tobago)
Retail
- Price Smart Trinidad (Chaguanas, Port of Spain & Mausica)