A pet water dispenser may include a water tank to store water and an inner assembly detachably coupled to the water tank and provided inside the water tank. The inner assembly may include a pump. A bottom plate of the water tank may be formed with a protrusion projecting upward, while the inner assembly may include a support cylinder having a cavity or recess that is inserted onto the protrusion. The support cylinder may include an upper surface and a sidewall to define the cavity or recess. The inner assembly may further include a filter coupled to the support cylinder.