The sap beetles, also known as Nitidulidae, are a family of beetles.

They are small (2–6 mm) ovoid, usually dull-coloured beetles, with knobbed antennae. Some have red or yellow spots or bands. They feed mainly on decaying vegetable matter, over-ripe fruit, and sap. Some sap beetle species coexist with fungi species and live in habitats of coniferous trees. These fungi-dependent beetles are found in all across Europe and Siberia and are the biggest nitidulid species known in those areas. Other species like the Australian Chychramptodes murrayi are known to feed on scale insects. There are a few pest species, like the strawberry sap beetle that infest crops in Brazil between the months of August and February.

Some common sap beetles include:

The oldest unambiguous fossils of the family date to the Early Cretaceous, belonging to the genus Crepuraea from the Aptian aged Zaza Formation of Russia.

The family includes these genera:^{[citation needed]}