A forceps includes first and second jaw members and at least one handle movable between an open position and a closed position for moving the jaw members between a spaced-apart position and an approximated position. A ratchet mechanism includes first and second ratchet components configured to engage one another upon movement of the at least one handle to the closed position to retain the jaw members in the approximated position. A knife is selectively movable between a retracted position and an extended position, wherein the knife extends between the jaw members to cut tissue therebetween. A safety mechanism is configured to inhibit extension of the knife when the jaw members are disposed in the spaced-apart position. Movement of the ratchet components into engagement with one another to retain the jaw members in the approximated position disengages the safety mechanism, thereby permitting extension of the knife.