A hearing device test adapter is provided in order to connect a hearing device output to a test microphone in a soundproof manner. The hearing device test adapter has an expandable first section for enclosing one section of a hearing device shell or an earmold piece in a soundproof manner such that the sound output of the hearing device shell or of the earmold piece points to the tip of the first section. In addition, the hearing device test adapter has an expandable second section for enclosing a section of the test microphone in a soundproof manner, with the tip of the first section directly connecting to the second section and both being connected to one another via a sound transmission.