The 2019 Data Release includes all data acquired during the fifth year of the NEOWISE Reactivation mission (Mainzer et al. 2014, ApJ, 792, 30), 13 December 2017 to 13 December 2018. These data are combined with the Year 1-4 NEOWISE data into a single archive that contains approximately 12.8 million sets of 3.4 and 4.6 micron images and a database of over 95 billion source detections extracted from those images.