Channel and playa uranium deposits are the most significant subclass of surficial uranium deposits globally. They form in arid/semi-arid regions within shallow (ca. 1–15 m depth) Cenozoic- to Quaternary-age paleochannel groundwater calcrete and associated smectitic fluvial/alluvial and playa-lacustrine sediments. The primary uranium mineral within these deposits is the potassium-uranyl-vanadate, carnotite (K2(UO2)2(VO4)2·1–3H2O). This chapter examines the global distribution and paragenesis of uranium mineralization in channel and playa uranium deposits, emphasizing the largest deposits in Western Australia and Namibia. Integrating geological, geomorphological, hydrogeological, and mineralogical observations from these deposits constrain the critical environmental and physicochemical factors essential to accumulating uranium into economically significant concentrations within a near-surface setting.