A safety stirrup having a frame structure, a hooking to a stirrup strap, a support element for the user's foot, and a first side arm to connect a first edge portion of the support element to the hooking portion. A second arm extending between a second edge portion of the support element and the hooking portion, when used by the user's foot. The second side arm hinged with a first end portion to the frame structure and rotatably movable between a closed position, wherein the second side arm laterally defines the stirrup opening, and an open position, wherein a free end of the second side arm, opposite the joint end portion allowing the sidewise exit of the user's foot. The second side arm at the end portion and movable integrally in the passage between the closed and open positions to guide the user's foot and preventing it from accidentally re-entering.