St Mark's was an English association club based in Windsor.

Its players were pupils and masters[1] attending St Mark's School, under the headmastership of the Reverend E. Hawtrey, whose sons played for the club.

[4] This appears to be because a number of its players had pledged their allegiance to other clubs in the Windsor and Slough area, including Swifts F.C.

[5] The club provided three players to the Berkshire Football Association representative side in 1876–77.

There were two London clubs active at the time under the name St Mark's; St Mark's Guild, a team from a teacher training college who changed their name to Rangers in 1877, and St Mark's College from Chelsea, a team of undergraduates from a college linked to the teacher training college, who played into the late 1880s, and whose old boys formed a football club (Old St Mark's F.C.)