A holographic weapon sight or holographic diffraction sight is a non-magnifying gunsight that allows the user to look through a glass optical window and see a holographic reticle image superimposed at a distance on the field of view.^[1] The hologram of the reticle is built into the window and is illuminated by a laser diode.

The first-generation holographic sight was introduced by EOTech—then an ERIM subsidiary—at the 1996 SHOT Show,^[2] under the trade name HoloSight by Bushnell, with whom the company was partnered at the time, initially aiming for the civilian sport shooting and hunting market. It won the Optic of the Year Award from the Shooting Industry Academy of Excellence.^{[citation needed]}

EOTech was the only company that manufactured holographic sights until early 2017, when Vortex introduced the Razor AMG UH-1 into the market as a competing product.^[3] As Vortex introduced the Gen II model on mid July, 2020 which later replaced the original UH-1.

Holographic weapon sights use a laser transmission hologram of a reticle image that is recorded in three-dimensional space onto holographic film at the time of manufacture. This image is part of the optical viewing window. The recorded hologram is illuminated by the collimated light of a laser diode built into the sight. The sight can be adjusted for range and windage by simply tilting or pivoting the holographic grating.^[4] To compensate for any change in the laser wavelength due to temperature, the sight employs a holography grating that disperses the laser light by an equal amount but in the opposite direction as the hologram forming the aiming reticle.

The optical window in a holographic weapon sight looks like a piece of clear glass with an illuminated reticle in the middle. The aiming reticle can be an infinitely small dot whose perceived size is given by the acuity of the eye. For someone with 20/20 vision, it is about 1 minute of arc (0.3 mrad).^{[citation needed]}

Holographic sights can be paired with "red dot magnifiers" to better engage farther targets.

Like the reflector sight, the holographic sight is not "parallax free", having an aim-point that can move with eye position. This can be compensated for by having a holographic image that is set at a finite distance with parallax due to eye movement being the size of the optical window at close range and diminishing to zero at the set distance, usually around the target range of 100 yards.^[5]

• Fire-control system
• Collimator sight
• Reflex sight
• Laser sight (firearms)
• Prism sight, a type of telescopic sight
• Glossary of firearms terminology
• Glossary of military abbreviations
• List of laser articles