The Diplophidae or portholefishes are a family of mesopelagic marine stomiiform fish found in deep waters worldwide.
The following two genera are placed in this family:
Previously, both genera were placed in the family Gonostomatidae. However, a 2025 phylogenetic study found this family to be paraphyletic as previously described, and found these genera to form a distinct early-diverging clade within the Stomiiformes, for which the old family name Diplophidae was revived.