We have conducted experiments to release oxygen from lunar soil samples, as part of a continuing study of lunar resource production. The 15 soils span the range of compositions in the Apollo collection. All were reduced in flowing hydrogen at temperatures of 900-1100°C. Oxygen yield is strongly correlated to initial iron oxide abundance, averaging 77% of total FeO. Oxygen release is relatively insensitive to mineralogy, with partial to total reduction of FeO in ilmenite, olivine, pyroxene, impact glass, and volcanic glass. The highest yields are from iron-rich mare soils and volcanic glass. These data provide “ground truth” for assessment of oxygen production from any lunar soil. Such assessment can be carried out from lunar orbit, using current data supplemented by observations from future missions.