Abstract: A lighting device for an air or gas filled balloon is disclosed. The device includes a cylindrical luminous element having an open end and a closed end, and being adapted to receive an illuminant, which may be an incandescent, chemical or solid state light source, at its open end. The luminous element is sized to fit through a balloon orifice when the orifice is stretched, yet maintain an effective seal therewith when in a non-stretched state. Various embodiments include auxiliary structures to enhance the seal between the balloon and the luminous element, to close the open end of the illuminant, to facilitate routing of electrical wires, to support the illuminant in the luminous element, to enhance support of the balloon relative to the luminous element, to tether the balloon to a fixed structure, and combinations of the above.