This article focuses on the natures, origins, and significances of clastic sediments in caves. Clastic sediments are fragments of preexisting rocks that have been transported and redeposited. Streams transport large quantities of clastic sediments through caves, including stream gravels and mud, but clastic sediments also move as gravity flows by slumping and sliding. Sedimentology and stratigraphy offer the means to understand the origins and transport mechanisms behind individual clastic deposits. Together, the two methodologies consider layering within deposits and grain sizes, sorting, mineralogies, and sedimentary structures within individual beds. Facies are recognized where those variables include diagnostic properties tied to particular depositional processes or driving forces. As is shown using examples, stratigraphy and facies analysis make it possible to reconstruct cave or landscape histories, including system responses to disturbances such as climate change and land use. Notably, system responses typically reflect changes in sediment supply, hydraulic gradients, or obstructions. These factors are recorded in passage morphologies, which should always be considered when studying clastic sediments in caves, and examples are cited.