This article is about the geologic period; for the North American culture, see Mississippian culture.

A now-defunct newspaper that was active in the nineteenth century was called The Mississippian, and was published in Jackson, Mississippi.

The Mississippian is a geologic (sub)period lasting from roughly 360 million years before the present (BP) to 325 million years BP. As with most other geologic periods, the rock beds that define the period are well identified, but the exact start and end dates are uncertain by a few million years. In North America, where the interval consists primarily of marine limestones, it is treated as a full-fledged geologic period between the Devonian and the Pennsylvanian. In Europe, the Mississippian and Pennsylvanian are one more-or-less continuous sequence of lowland continental deposits and are lumped together as the Carboniferous period.

Refer to the Carboniferous period article for information on faunal stages, climate, etc.