A cloaking device, also known as a cloaking shield, is a form of stealth technology that uses selective bending of light and other forms of energy to render a starship or other object completely invisible to the electromagnetic spectrum and most sensors. Most vessels could not use their weapons and deflector shields when cloaked.

Cloaking technology existed in the galaxy for some time, however in the affairs of the major Alpha and Beta Quadrant powers the technology only started to come into use in the 22nd century. they were mostly used by the Suliban Cabal, Romulans and the Klingon.

In the 24th century, the Federation protected its borders from cloaked Romulan incursion by a gravitic sensor net. With the signing of the Treaty of Algeron, in 2311, the Federation explicitly agreed not to develop or use cloaking technology.

Following the outbreak of hostilities with the Dominion in late 2370, the Romulan Empire allowed the use of one of their own cloaks aboard the USS Defiant, to be used only in the Gamma Quadrant. In exchange, Starfleet had to provide all the intelligence it received on the Dominion.

By the late 32nd century, Starfleet vessels were subsequently refitted with cloaking technology (as the Treaty of Algeron was nullified with Vulcan/Romulan reunification).