The data collected during the first 34 months of the Gaia mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC), resulting in Gaia's third data release, Gaia DR3. Gaia DR3 contains the astrometry and broad-band photometry already published as part of Gaia EDR3 and introduces a large variety of new data products. A summary of the release properties is provided in Gaia Collaboration et al. (2022). The overall scientific validation of the data is described in Babusiaux et al. (2022) and Fabricius et al. (2021) (astrometry and broad-band photometry). Background information on the Gaia mission and the spacecraft can be found in Gaia Collaboration et al. (2016). In addition, Gaia DR3 is accompanied by dedicated processing papers, all part of a Special Issue of A&A, that describe the processing and validation of the various data products. The data release documentation provides complementary information to the processing papers. Finally, nine performance verification papers accompanying Gaia DR3 co-authored by the Gaia Collaboration provide an impression on the immense scientific potential of this release.