Several proposed and performed experiments for the measurement of quantum and gravitational effects in ring interferometers of various types (with neutrons, superconducting electrons and superfluid helium as well as photons) are discussed in a unified framework. The earth's rotation and local gravity have been detected in some but not other of these interferometers. The reasons for this are discussed, as well as the extent to which the results support theories of gravity at the quantum level. Several interferometers have reached the limits of resolution imposed by quantum noise. Experiments under construction aim to detect non-newtonian gravitational effects at the level of 10−9of the effect induced by earth rotation.