UY Scuti is a red hypergiant and pulsating star in the constellation Scutum. It is currently the largest known star.

First cataloged in 1860 by German astronomers, the star has an estimated radius of 1,708 solar radii (1.188×109 kilometres; 7.94 astronomical units); thus a volume nearly 5 billion times that of our Sun. A hypothetical object travelling at the speed of light would take about seven hours to travel around UY Scuti, whereas it would take 14.5 seconds to circle the Sun.

The star is about 9,500 light years from Earth. If placed at the center of our Solar system, its photosphere would engulf the orbit of Jupiter. The radius is not known for certain, and may be larger than the orbit of Saturn.

Under good conditions with no light pollution, UY Scuti can be seen using a small telescope or large binoculars as a reddish star with a faint smudge along the stars of the Milky Way. It is located a few degrees north of the A-type naked-eye star Gamma Scuti, and 2 arcminutes northwest of the Eagle Nebula.