| Sean Mcnamee Hardware Ltd | Wholesale & retail | 2023 |
| Sedan Construction Limited | Construction | 1987 |
| Shanmullagh Developments Ltd | Construction | 2000 |
| SI Energy Ltd | Agriculture & fishing | 2006 |
| Silcon Systems Ltd | Construction | 2002 |
| Smallwood Contracts Ltd | Manufacturing | 2003 |
| Spout Lane Management Ltd | Households | 2001 |
| Springisland Supermarket Limited | Wholesale & retail | 2004 |
| Stamore Properties Ltd | Wholesale & retail | 2006 |
| Stanley Bell and Sons Limited | Mining & quarrying | 2006 |
| Starplan Enterprises Ltd | Wholesale & retail | 1976 |
| Starplan Furniture Limited | Manufacturing | 1983 |
| Strabane Electrics Ltd | Construction | 2006 |
| Strabane Training Services (1990) Limited | Other services | 1991 |
| Strabane Training Services Limited | Real estate | 1978 |
| Supermix Limited | Manufacturing | 1987 |
| Taggart Electrical Ireland Limited | Construction | 2006 |
| Tamlaght Developments Ltd | Construction | 2007 |
| Tamlaght Estates Ltd | Construction | 2004 |
| Tara Centre | Other services | 1999 |
| Taylors (Fyfin) Limited | Wholesale & retail | 1977 |
| Tempus Investments Limited | Construction | 2006 |
| Tereco Limited | Water & waste | 2006 |
| Thomas Oliver and Associates Limited | Professional & scientific | 2007 |
| Thos. Scarffe & SON Limited | Real estate | 1956 |
| Titan (RAK) Limited | | 2006 |
| TMG Alloy Wheels Ltd | Wholesale & retail | 2004 |
| TOM Morrow & Company Limited | Wholesale & retail | 1978 |
| Traynors Ltd | Wholesale & retail | 1992 |
| Tri-Car (NI) Ltd | | 1995 |
| Tullydraw Properties Ltd | Construction | 2002 |
| Tyre Safety Centre (Co.Tyrone) Limited | Wholesale & retail | 1971 |
| Tyressan Farm Ltd | Agriculture & fishing | 2002 |
| Tyrestores (NI) Limited | | 1991 |
| Ulster Farmer's Mart Company Limited | Wholesale & retail | 1947 |
| Universal Finance (Omagh) Limited | Financial services | 2004 |
| Upward Investments Limited | Real estate | 1997 |
| Varamac Limited | Construction | 2003 |
| Voltac Limited | Wholesale & retail | 1990 |
| Vono (UK) Limited | | 1994 |
| W T Hire Strabane Limited | Administrative & support | 2003 |
| W. Todd & SON Ltd | Financial services | 2006 |
| W.F. Mccurdy & Co Limited | Construction | 2003 |
| W.O. Young & Sons (Feeds) Ltd | Agriculture & fishing | 1997 |
| Watterson Brothers (Omagh) Limited | Wholesale & retail | 1975 |
| Western Building Systems Ltd | Construction | 1991 |
| Westmount Construction Limited | Construction | 2002 |
| Whirling Limited | Professional & scientific | 2006 |
| William Bell (Tractors) Limited | Wholesale & retail | 1977 |
| William ST. Ltd. | Real estate | 2006 |
| Wilmar Leisure Limited | Real estate | 2007 |
| X-Cellance Flooring Limited | Construction | 2007 |