Sphaeromatidae is a family of isopods, often encountered on rocky shores and in shelf waters in temperate zones.

[1] The family includes almost 100 genera and 619 known marine species (and about 65 in fresh water).

Within these genera, there are groups that share distinctive morphologies; further research may reclassify these genus-groups as separate families.

[2] Many species have a dorsoventrally compressed body shape, often with a vaulted dorsum, and some are strongly flattened (scale-like).

[3] Some genera of Sphaeromatidae associate with sponges, particularly Oxinasphaera.