Euclid will greatly advance galaxy cluster science, in both cosmology and astrophysics, by providing a large catalog of clusters extending to redshifts well beyond unity and with high quality gravitational lensing measurements. This is a joint meeting of the Galaxy Cluster Science Working Group (SWG) and OU-LE3 group of the science ground segment. The meeting will cover critical areas of on-going work in the preparation of mission data analysis.