An apparatus for sealing and illuminating a balloon includes a housing for sealing insertion into a neck of a balloon. A flow path within the housing conducts an inflation gas from an inlet to an outlet of the housing, and a flow control system disposed in the flow path allows the inflation gas to flow from the inlet to the outlet. The apparatus includes a light source mounted in conjunction with the housing and a power source disposed within the housing providing power for the light source. A switch mounted in conjunction with the housing is operable to selectively connect the power source to the light source by completing a circuit between the power source and the light source. The apparatus also includes a switch activating member annularly disposable around the housing to operate the switch.