Both oviparous (egg-bearing) and larviparous (larvae-bearing) species are known within Ostreidae.

However, the larviparous species show a pattern of alternating sex within each individual, whereas the oviparous species are simultaneous hermaphrodites, producing either female or male gametes according to circumstances.

Members of genus Ostrea generally live continually immersed and are quite flat, with roundish shells.

They differ from most bivalves by having shells completely made up of calcite, but with internal muscle scars of aragonitic composition.

Members of genera Saccostrea, Magallana, and Crassostrea generally live in the intertidal zone, broadcast sperm and eggs into the sea, and can thrive in eutrophic water.