• 1999 - Gold Unit Award
• 1998 - Gold Unit Award
• 1997 - Gold Unit Award
• 1996 - Gold Unit Award and Best Unit
• 1995 - Gold Unit Award
• 1994 - Gold Unit Award

Gan Eng Seng School received the Sustained Achievement Awards 2000 through two Uniformed Groups, NCC and Scouts.

Best NCC Land Unit - Chief of Defence Challenge Trophy

Gold Unit Award and Best Unit

Most Outstanding Cadet MSG Cheong Jiawen

Most Outstanding CLT: S/CLT Victor Koh

Gan Eng Seng School received the Sustained Achievement Awards 2001 through two Uniformed Groups, NCC and Scouts.

NCC Land Unit

NCC Best Unit Competition 2003 - Gold

Most Outstanding Cadet MSG Loh Chee Mun.

1st Runner-up for Best Unit/Boys and Girls

Gan Eng Seng School received the Sustained Achievement Awards 2002 through two Uniformed Groups, NCC and Scouts.

NCC Land Unit

• NCC Best Unit Competition 2002 - Gold
• Overall First in the Best Unit Competition 2002
• Chief of Army Challenge Trophy in the Best (Land) Boy Unit Category 2002

The Sec 2 NCC boys won an award in November.

In the Inter-Unit M16 Shooting Competition organised by HQ NCC, we came in Team - 3rd.

Most outstanding cadet: MSG Calvin Tay

Most outstanding CLT: S/CLT Goh Ghim Song

Gan Eng Seng School received the Sustained Achievement Awards 2003 through two Uniformed Groups, NCC and Scouts.

NCC Land Unit

NCC Best Unit Competition 2003 - Gold

Most Outstanding Cadet: MSG Andy Hoe

Gan Eng Seng School received the Sustained Achievement Awards 2004 through two Uniformed Groups, NCC and Scouts.

NCC Land Unit

NCC Best Unit Competition 2004 - Gold

Most Outstanding Cadet: MSG Oh Eng Shaw

Gan Eng Seng School received the Sustained Achievement Awards 2005 through two Uniformed Groups, NCC and Scouts.

NCC Best Unit

NCC Best Unit - Gold Award

NCC Best Unit

NCC Best Unit - Gold Award

Outstanding Cadet Award

Outstanding Cadet Award - MSG Xu Kai Sheng

NCC Best Unit

NCC Best Unit - Gold Award

NCC Best Unit

NCC Best Unit - Gold Award

NCC Best Unit

NCC Best Unit - In Progress