Abstract: A gas-discharge lamp has an envelope which accommodates a longitudinally extending high-pressure inner tube which is secured to current leads sealed in a stem of the envelope. At least one-half of the entire inner surface of the envelope has a reflector coating applied in such a manner that a plane drawn through extremities of the reflector coating runs in parallel with a longitudinal axis of the high-pressure inner tube. The envelope is of a cross-sectional configuration in which the distance from the axis of the inner tube to the surface of the reflector coating varies continuously. The ratio of the shortest distance (r.sub.min) from the axis of the inner tube to the surface of the reflector coating to the respective maximum distance ranges from 0.6 to 1.0.