[en] Energetic photons impinging on surfaces of solids can cause gas release by photodesorption, photodecomposition, and photocatalysis. Experimental data on x-ray induced gas adsorption and gas release from surfaces will be reviewed. Results from experiments using photons of lower (e.g. visible or uv-range, synchrotron radiation) or higher energy (γ-rays) will only be included in the review to the extent they are needed to interpret the data obtained with photons in the x-ray range. The importance of x-ray induced photodesorption in the attainment of ultrahigh vacuum in electron storage rings and in plasma containment experiments will be discussed