Abstract: An apparatus for filling expandable toy balloons with a liquid such as water includes a body portion defining a central cavity and having a pair of open ends, with the lower end formed into a fitting member for releasable engagement of the neck of a balloon, and the upper end formed into a mouthpiece for the user's mouth. The neck of the balloon to be filled is placed over the fitting member and the entire apparatus (with balloon attached) is then at least partially filled with water by dipping into a body of water. The user then places his mouth on the mouthpiece and exhales into the body portion and central cavity, to displace the water into the balloon until the balloon has been filled with water to the desired level. The filled balloon can then be removed from the fitting, and the neck of the balloon tied off in a knot, so that the water balloon may be used for play.