The Gracillariidae are a family of over 1,900 species of very small moths in the superfamily Gracillarioidea. They occur worldwide, with highest diversity in the tropics; about 200 species are recorded in North America. The family was established by Henry Tibbats Stainton in 1854.

Adults have wingspans of 5–15 mm, narrow wings often with metallic or bright markings, and are held roof-like at rest. Most are diurnal. Larvae are leaf miners, creating blotch or serpentine mines in a wide range of plants, including trees, shrubs, and herbs; early instars are sap-feeders with flattened bodies, later ones become cylindrical. Several species are agricultural pests, such as Phyllocnistis citrella (citrus leafminer), Cameraria ohridella (horse-chestnut leafminer), and Phyllonorycter blancardella (apple leafminer).

The family includes subfamilies such as Gracillariinae (with genera Phyllonorycter, Caloptilia, and Cameraria), Lithocolletinae, and Ornixolinae. Many species remain undescribed, especially in Asia and South America. Recent studies use DNA barcoding and mine morphology for identification.