| St. John's College, Colombo | |
| Motto: | Be a Man |
| Location: | Dematagoda Road, Dematagoda, Colombo |
| Country: | Sri Lanka |
| Coordinates: | 6.9308°N 79.8736°W |
| Pushpin Map: | Sri Lanka Colombo Greater |
| Pushpin Map Caption: | Location in greater Colombo |
| Pushpin Label Position: | right |
| Type: | High school |
| District: | Colombo |
| Grades: | 1 - 13 |
| Colors: | Dark blue, sky blue and white |
St. John's College, Colombo (Sinhala : ශාන්ත ජෝන් විද්යාලය) is a Government school for boys which is hosted by Western Provincial Council. In here about 1,100+ students are studying. This school was established on 16 January 1939 by Rev. Maurice John Legoc. The first principal was B. Wean Sander.