Sir John Brian Pendry, is an English theoretical physicist known for his research into refractive indices and creation of the first practical "Invisibility Cloak". He is a professor of theoretical solid state physics at Imperial College London where he was head of the department of physics (1998–2001) and principal of the faculty of physical sciences (2001–2002). He is an honorary fellow of Downing College, Cambridge, and an IEEE fellow. He received the Kavli Prize in Nanoscience "for transformative contributions to the field of nano-optics that have broken long-held beliefs about the limitations of the resolution limits of optical microscopy and imaging.", together with Stefan Hell, and Thomas Ebbesen, in 2014.

Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible. The phenomenon is studied by physics and perceptual psychology.