A barbed suture includes a flexible thread having a core with a leading end, a trailing end, and a central axis. The barbed suture includes a first flexible flap connected to the core, the first flap extending between the leading and trailing ends of the core, and a second flexible flap connected to the core, the second flap extending between the leading and trailing ends of the core. The flexible flaps and the core have an S-shaped profile when viewed in cross-section. The barbed suture includes first and second slots formed in the respective first and second flaps for dividing the flaps into first and second barbs projecting from the core, whereby each slot extends outwardly from the core and rearwardly toward the trailing end of the core.