Macroplata (meaning "big plate") is an extinct genus of Early Jurassic rhomaleosaurid plesiosaur which grew up to 4.65 metres (15.3 ft) in length.

It is known from a nearly complete skeleton NHMUK PV R5488 (formerly BMNH R 5488) from the Blue Lias Formation (Hettangian) of Harbury, Warwickshire, UK.

Together, they form the rounded region at the front of the jaw, and have a rough outer surface bearing foramina, ridges, and grooves.

While the premaxillae become narrow beyond this point, they extend far back on the skull, forming a ridge rearward of the external nares.

The teeth of Macroplata have circular cross-sections and possess vertical ridges that all at least come close to the tooth's tip (few actually reach it).

The frontals are separated from each other by the premaxillae in the front and the parietals (bones at the back of the skull roof) at the rear, with a small area of contact between.

The postfrontals form the border between the orbits and the temporal fenestrae, and each bone bearing a ridge running perpendicularly to the skull's length.

[1] The parasphenoid (a midline bone in the rear part of the palate) is smooth and approximately diamond-shaped, with a wide surface at its front that articulates with the pterygoids.

The occipital condyle is formed solely by the basioccipital, with the exoccipital-opisthoics (side bones of the rear braincase) not participating.

The paraoccipital processes (the elongated regions of the exoccipital-opisthoics) of the latter bones bear wide upper surfaces and slope downwards and forwards.

Beyond the axis, the undersides the cervical centra bear keels, with a prominent pit on each side in which a small subcentral foramen (holes on the bottom of the vertebrae) is located.