Archaeocalamitaceae is a family of extinct sphenopsids related to horsetails.

Archaeocalamite fossils have been found in Siberia, Poland, and Brazil.

The fossils date to the Middle Devonian-Carboniferous, lower Carboniferous (Dinantian), and the lower Permian respectively.

[1][2][3] Given the distance of the fossil discoveries, archaeocalamites may have had a subcosmopolitan distribution.

[citation needed] Possible relationships archaeocalamites has with other sphenopids is shown below.