Stiphodon martenstyni, the Martenstyn's stiphodon or Martenstyn's goby, is a species of amphidromous freshwater goby endemic to the southwestern portion of Sri Lanka. The males of this species can reach a length of 3.4cm (01.3inches) SL.
The specific name martenstyni is named in memory of Cedric Martenstyn, who was a leading naturalist of the country killed by the Tamil militant organization Liberation Tigers of Tamil Eelam (LTTE).