Mytilida is an order of marine bivalve molluscs, commonly known as true mussels. There is one extant superfamily, the Mytiloidea, with a single extant family, the Mytilidae.

Perna viridis, known as the Asian green mussel, is an economically important species of mussel, a bivalve belonging to the family Mytilidae, or the "true mussels". It is harvested for food, but can ha