R-Type Delta is a horizontally scrolling shooter video game released only on the PlayStation. It is the fourth game in the R-Type series (hence Delta, the fourth letter of the Greek alphabet) and also the first game in the R-Type series rendered in full 3D graphics.

It is the year 2163. The trans-dimensional fighter R-9A Arrowhead has returned from its mission to destroy the evil at the center of the Bydo Empire. Badly damaged, it has been rescued by the battle-cruiser Croque-Monsieur, and brought back to Earth's orbital space fortress, Aegis.

Astronomers in Central Asia watched as strange objects began to fall from the sky. As the objects approached closer to the Earth, they shrank in size and disappeared from sensors. The astronomers, assuming the objects to be meteorites, paid them no further attention.

Before long, the electronically-controlled weapons systems in a number of cities went haywire and several abnormal heat signatures were detected by astronomers. Bydo influence caused control of the orbiting annihilation platform, Moritz-G, to be lost and it was subsequently unleashed upon the Earth.

The Moritz-G descended on a city in Asia, its planet-destroying capability has not yet activated, but its self-defense system has thwarted all attempts to approach it. An emergency military operation has been put into effect, and the test fighter R-9A2 Delta has been assigned to the attack force.