Platyhydnobius is a genus of beetles in the family Leiodidae. They have Nearctic and northern Neotropical distribution, from Honduras north to Alaska and Newfoundland.
Platyhydnobius are small beetles, measuring about in length (pronotum+elytra). The genus name refers to the broad and flat shape of the parameres in this genus, in combination with a reference to the genus Hydnobius.
There are eight recognized species: