- Aeronautical Society
- Art Club
- Association of Innovation and Design
- Association of Science and Technology
- Automobile Club
- Buddhist Students’ Association
- Canto Perpetua Choir
- Carnatic Orchestra
- Classical Music Association
- Commerce Society
- Cubing Society
- Culinary Arts Society
- English Drama Society
- English Lit & Debating Society
- Gavel Club
- Geography Society
- Health Club
- Hewisi Band
- Hindu Students’ Union
- Histoarcheo Club
- HNB Students’ Savings Unit
- ICT Society
- Interact Club
- Islamic Society
- Junior English Lit & Debating Society
- Junior Maths Society
- Junior Science & Technology
- Kennel Club
- Media Unit
- Photographic Club
- Political Science Society
- Productive Citizenship Society
- Quiz Club
- Scuba Diving Unit
- Radio Club
- Red Cross Society
- Road Safety Patrol
- Senior Environmental Club
- Seylan Bank Students’ Savings Unit
- Sinhala Literary & Debating Society
- Society for Social Work & Welfare
- Spelling Union
- Student Christian Movement
- Tamil Drama Society
- Tamil Literary and Debating Society
- The Ternion
- Thomian Union
- United Nations Club
- Western Band
- Wildlife Society
Gavel Club
The Gavel Club focuses on the development of communication skills of students. The club is associated with Toastmasters International. The club meeting maintains basic formalities and bases itself on a new topic every week with pre planned events taking place as part of an organised agenda. The club also associates with and participates with other gavel clubs and events and invites Toastmasters to meeting on occasion.Latest Project
Joint meeting with Pinnacle Gavel Club
The Pinnacle Gavel Club and the Gavel Club of S. Thomas' College participated in a joint online session, in which members of both clubs took part in a programme and interacted with one another.