| Koh Boon Haw | 4980 | Chemical | 2017-10-23 | Aster Chemicals and Energy Pte Ltd |
| Koh Boon Liang | 2461 | Civil | 1989-03-22 | Ronnie & Koh Consultants Pte. Ltd. |
| Koh Chan Ghee | 3182 | Civil | 1995-10-18 | National University Of Singapore |
| Koh Chee Keong | 4621 | Electrical | 2014-08-21 | SP Group |
| Koh Chee Lin | 5544 | Mechanical | 2023-05-18 | Ministry of Manpower |
| Koh Chee Loong | 3097 | Civil | 1995-02-15 | - |
| Koh Chin Chin | 4638 | Civil | 2014-10-21 | Lendlease Asia Holdings Pte. Ltd. |
| Koh Chin Hua | 5261 | Mechanical | 2019-10-17 | Icon Engineers LLP |
| Koh Chin Kok | 3319 | Civil | 1997-05-20 | Surbana Jurong Consultants Pte. Ltd. |
| Koh Choon Teck | 5450 | Civil | 2022-01-27 | AECOM Singapore Pte Ltd |
| Koh Choon Tee | 3991 | Mechanical | 2005-08-09 | Squire Mech Private Limited |
| Koh Danny | 3763 | Civil | 2002-10-03 | - |
| Koh Eik Kuang | 4604 | Civil | 2014-06-23 | SWC Builders & Engineering Pte. Ltd. |
| Koh Eng Wah Bernard | 3633 | Electrical | 2001-06-12 | PUB, Singapore's National Water Agency |
| Koh Ji Lit | 5641 | Civil | 2024-05-23 | KTP Consultants Pte Ltd |
| Koh Kah Yong | 2893 | Civil | 1993-01-20 | CWMCE Pte. Ltd. |
| Koh Kar Jun | 5920 | Mechanical | 2026-06-25 | Building And Construction Authority (BCA) |
| Koh Kay Tee | 1487 | Civil | 1980-08-19 | Tritech Consultants Pte. Ltd. |
| Koh Khim Hun | 3723 | Electrical | 2002-06-21 | - |
| Koh Kiat Kim | 3932 | Civil | 2004-10-19 | JTC Corporation |
| Koh Kin Teng | 3696 | Mechanical | 2002-03-19 | - |
| Koh Kok Keang @ Koo Sio Keang | 3893 | Civil | 2004-05-05 | Beca Carter Hollings & Ferner (S.E.Asia) Pte Ltd |
| Koh Kok Kwan | 3645 | Electrical | 2001-08-21 | Resorts World Sentosa Pte. Ltd. |
| Koh Kok Peng @ Koh Koh Pen | 2913 | Civil | 1993-04-21 | K P Koh & Partners Pte Ltd |
| Koh Lian Suan Adeline | 3211 | Electrical | 1996-03-06 | WSP Consultancy Pte. Ltd. |
| Koh Nghee Kwang | 2403 | Civil | 1988-05-18 | LMO & Associates Pte Ltd |
| Koh Siew Lim Banny | 4055 | Mechanical | 2006-06-20 | SP Group |
| Koh Teck Kuan | 5027 | Electrical | 2018-03-15 | Ngee Ann Polytechnic |
| Koh Tong Jun | 5723 | Civil | 2025-01-23 | PUB, Singapore's National Water Agency |
| Koh Wee Kian | 5894 | Electrical | 2026-05-28 | Surbana Jurong Consultants Pte. Ltd. |