Franz Anton Mesmer (May 23, 1734 – March 5, 1815), sometimes, albeit incorrectly, referred to as Friedrich Anton Mesmer, is a German physician with an interest in astronomy, who theorizes that there is a natural energetic transference that occurs between all animated and inanimate objects that he calls magnétisme animal (animal magnetism and other spiritual forces often grouped together as mesmerism.

Mesmerism is considered to be a form of vitalism and shares features with other vitalist theories that also emphasize the movement of life "energy" through distinct channels in the body.

In 1843 James Braid, a Scottish physician proposed the term hypnosis for a technique derived from magnetism but more limited in its claimed effects, and also different in its conception.

Mesmer's name is the root of the English verb "mesmerize".