The Kaili Formation (simplified Chinese: 凯里组; traditional Chinese: 凱里組; pinyin: Kǎilǐ zǔ) is a stratigraphic formation which was deposited during the Lower and Middle Cambrian (~513 to 506 million years ago).

The formation is approximately 200 metres (660 ft) thick and was named after the city Kaili in the Guizhou province of southwest China.

For example, the arthropod Skania similar to the Ediacaran Parvancorina of the Neoproterozoic age Ediacara Hills of South Australia has been found at the Kaili site.

[3][4] Some other notable fossils discovered at Kaili are putative invertebrate eggs and embryos,[5] trace fossils of the genus Gordia (not to be confused with the Gordian worms),[1] as well as Naraoia, chancellorids, Microdictyon, Wiwaxia, and Marrella.

The FAD of two trilobites from the formation are proposed to be the official stage boundary, Oryctocephalus indicus and Ovatoryctocara granulata.