A rotating and locking conveyor side guard system may include an elongate side guard of sheet material having three longitudinal bolt slots therethrough, one at each end and one at the center, and three bolts for securing the side guard to a side of a conveyor through the bolt slots. With the bolts loosened, a user may slide the side guard from side to side, relative to the conveyor, and rotate the side guard about the center bolt to a substantially perpendicular orientation to allow access to an interior of the conveyor through the side of the conveyor. It may then be rotated in a second direction until the first and second bolt slots engage corresponding bolts, in a locked position, to prevent rotation of the side guard. Some systems may include multiple side guards end-to-end in series, each side guard sharing a bolt with each adjoining side guard.