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.

Common types: Some common sap beetles include:

• the picnic beetle, Glischrochilus quadrisignatus
• the dusky sap beetle, Carpophilus lugubris
• the strawberry sap beetle, Stelidota geminata
• the small hive beetle, Aethina tumida

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.

Classification: The family includes these genera:

• Subfamily Calonecrinae Kirejtshuk, 1982
• Subfamily Maynipeplinae Kirejtshuk, 1998
• Subfamily Epuraeinae Kirejtshuk, 1986
• Subfamily Carpophilinae Erichson, 1842
• Carpophilus Stephens, 1830
• Epuraea Erichson, 1843
• Urophorus Murray, 1864
• Subfamily Amphicrossinae Kirejtshuk, 1986
• Subfamily Meligethinae Thomson, 1859
• Meligethes Stephens, 1830
• Pria Stephens, 1830
• Subfamily Nitidulinae Latreille, 1802
• Amphotis Erichson, 1843
• Cychramus Kugelann, 1794
• Cyllodes Erichson, 1843
• Ipidia Erichson, 1843
• Miskoramus Kirejtshuk & Lawrence, 1992
• Nitidula Fabricius, 1775
• Omosita Erichson, 1843
• Physoronia Reitter, 1884
• Pocadius Erichson, 1843
• Soronia Erichson, 1843
• Thalycra Erichson, 1843
• Tumida Murray, 1867
• Subfamily Cillaeinae Kirejtshuk & Audisio, 1986
• Cillaeopeplus Sharp, 1908
• Subfamily Cryptarchinae Thomson, 1859
• Cryptarcha Shuckard, 1839
• Glischrochilus Reitter, 1873
• Pityophagus Shuckard, 1839
• Subfamily Cybocephalinae Jacquelin du Val, 1858 (now frequently elevated to family status as Cybocephalidae)
• Cybocephalus Erichson, 1844
• Pastillus Endrödy-Younga, 1962
• Subfamily Prometopinae
• Prometopia
• incertae sedis
• Apetinus
• Conotelus
• Cyrtostolus
• Eunitidula
• Eupetinus
• Gonioryctus
• Goniothorax
• Haptoncus
• Kateretes
• Nesapterus
• Nesopetinus
• Notopeplus
• Orthostolus
• Stelidota
• Urophorus