Placunidae, also known as windowpane oysters, windowpane shells, and Capiz shells, are a taxonomic family of saltwater clams, marine bivalve mollusks which are related to oysters and scallops.

This family is best known for the shells of the species Placuna placenta, which are translucent, and are commonly used in shellcraft production.

One of the main differences is that the Placunidae do not attach themselves to a hard surface but are instead a mud-living family.

Species in the family Placunidae are extensively collected in the Indo-West Pacific, and are cultivated or farmed in several areas.

The shells were originally used as a glass substitute in glazing, but nowadays they are mainly used in the manufacture of trays, lampshades and numerous decorative items.