A bicycle sprocket comprises a sprocket body and chain-driving teeth. The chain-driving teeth comprises at least one first tooth and at least one second tooth. The at least one first tooth has a first circumferential tooth-length defined in a circumferential direction at a radial location defined in vicinity of a reference line. The at least one second tooth has a second circumferential tooth-length defined in the circumferential direction at the radial location. The first circumferential tooth-length is larger than the second circumferential tooth-length. A dimensional difference between the first circumferential tooth-length and the second circumferential tooth-length is equal to or smaller than 1 mm.