A snap hook has a body, a sliding latch, a resilient element, a swivel and a connector. The body has a shaft and a hook. The shaft is tubular and has an upper end and a lower end. The hook is connected to and extends from the upper end of the shaft. A guide slot is defined longitudinally the shaft and communicates with the lower end of the shaft. Accordingly, no sharp edges are formed near the sliding latch so a person opening the snap hook will not be injured. In addition, assembling the snap hook is easy.