The upper part of the crest shows a creature with a lion head, eagle wings and a dragon body with claws, representing the fact that the School was founded when Singapore was a British colony, by the American Methodist Mission, and during the Manchu dynasty in China.
The lower part of the ACS Crest comprises a panel of blue and another of gold, representing the heavens and the earth. Superimposed on them are the letters ACS in red, signifying life bridging earth and heaven.
The ACS Crest is shaped as a shield to uphold knightly values such as chivalry, honour, valour, loyalty and manliness. The letters 'ACS', besides being the initials of the school's name, also spell Academic achievements, Christian Character, and Sportsmanship and Service beyond self. The crest was designed in 1930 by the late Dr Yap Pheng Geck who was then a member of the staff.
The school motto, The Best Is Yet To Be, which was later introduced by the late Mr. T.W. Hinch (Principal,1929- 1947), was incorporated into the crest.