3D micro X-ray fluorescence analysis (3D Micro-XRF) is a non-destructive method for the investigation of elemental compositions of specimens with which three-dimensionally resolved information can be obtained. This is rendered possible through the formation of a probing volume resulting from the overlap of a condensed X-ray beam and the acceptance of a polycapillary lens in front of an energy-dispersive detector. Various setup schemes have been developed in the last years, which can be divided into synchrotron instrumentation and X-ray tube based spectrometers. Established in 2003/2004 numerous applications have been published up until now. Quantification of data though is still a topic of considerable interest and has been reported only for limited number of publications. This review aims to give an overview of work on quantitative 3D Micro-XRF. As the method can be applied with adapted setups to a variety of analytical problems, quantification also has to be flexible and different schemes have been developed.