Fyzikální Ústav AV ČR, v. v. i. (FZU; in English: Institute of Physics of the Czech Academy of Sciences) is a public research institute, oriented on the fundamental and applied research in physics. The founder of the institute is The Czech Academy of Sciences.
The present research programme of the Institute comprises five branches of physics: particle physics, the physics of condensed matter, solid state physics, optics and plasma physics. It also corresponds to the way how the institute is divided into major research divisions.