Nd:YAG is an acronym for Neodymium-doped Yttrium Aluminum Garnet, a compound that is used as the lasing medium for certain solid-state lasers. Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 940, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode.

Other common host materials for neodymium are: YLF (yttrium lithium fluoride, 1047 and 1053 nm), YVO (yttrium vanadate, 1064 nm), and glass. A particular host material is chosen in order to obtain a desired combination of optical, mechanical, and thermal properties. Nd:YAG lasers and variants are pumped either by flash lamps, continuous gas-discharge lamps, or near-infrared laser diodes.

For many applications, the infrared light is frequency-doubled or -tripled in order to obtain visible (527 or 532 nm, green) or ultraviolet light.

Recently, affordable laser pointers emitting a green beam based on a frequency doubled Nd:YAG laser have become available. Much brighter than the common red laser pointers, the beam can be seen in midair.