Lagenida is an order of benthic foraminiferal rhizaria in which the tests (shells) are monolamellar, with walls composed of optically and ultra-structurally radiate calcite, with the crystallographic c-axes perpendicular to the surface.

Lagenida (suborder Lagenina in Loeblich and Tappan 1988) is an emendation of the rotaliid superfamily Nodosariacea, removing it from the Rotaliina in the Treatise on Invertebrate Paleontology (Loeblich and Tappan, 1964) and combining it with the Robuloidacea, named by Reiss, 1963, to form a new order Lagenida.

Provided that robuloidaceans did actually give rise to nodosariacea in the Triassic, the ultimate ancestry of Lagenida can be found within Fusulinida, but not the better known Fusulinacea.

Shells (tests) of Lagenida are generally serial in form, with chambers in a line.

In both, when a new chamber is formed a new layer of material is added to the outer surface of the entire shell.