A tool holder that can be attached to an end of a spindle of a drilling and/or hammering tool and removed therefrom, the tool holder having a tool holder body that can be inserted into the end of the spindle and retained therein by means of at least one locking element that is movable in a radial direction to retain, or to allow release of, the tool holder body, a locking ring for holding the or each locking element in a position that retains the tool holder body in the spindle, and a manually operable sleeve that is associated with the locking ring characterised in that the manually operable sleeve enables a user to rotate the locking ring between a locking position and a release position, wherein the or each locking element is located in an aperture in the spindle, and will engage a depression in the tool holder body to retain the tool holder body in the spindle, so that the tool holder body can be retained in the spindle only when the tool holder body is in a defined orientation with respect to the axis of the spindle. wherein the locking ring has an internal radius that varies along its circumference so that rotation of the locking ring about the axis of the tool holder body will move it between the locking position in which it causes the or each locking element to retain the tool holder body in the spindle, and the release position in which it will allow the or each locking element to move radially to release the tool holder body and further characterised in that the locking ring has a region of relatively large internal radius forming a pocket that can receive a locking element when the element is in its radially outermost position, and a region of relatively small internal radius that can receive the locking element only when the locking element is in a radially inner position in which it engages its depression wherein the locking ring is biased with respect to the tool holder body into its locking position, the manually operable sleeve is rotatable with respect to the locking ring to a limited extent, the manually operable sleeve is rotatable with respect to the tool holder body to a limited extent, and the locking ring is held in its locking position against the bias by means of the manually operable sleeve, wherein the tool holder body can be inserted in the end of the spindle so that the or each locking element is in its radially outermost position and is received in a pocket of the locking ring, and manual rotation of the sleeve in one sense will cause the tool holder body to rotate with respect to the spindle but the locking ring will be prevented from rotating with respect to the spindle by means of the or each locking element until the or each depression is in circumferential register with a locking element, whereupon the or each locking element will move radially inwardly into its depression and allow the locking ring to rotate under the bias into its locking position, and wherein, when the tool holder is inserted in the end of the spindle and the locking ring is in its locking position, manual rotation of the sleeve about the spindle in the opposite sense will cause the locking ring to rotate together with the sleeve against the bias until the or each locking element is in register with a pocket of the locking ring, whereupon the or each locking element will move radially outwardly into its pocket to allow removal of the tool holder.