Harold Clayton Urey (1893-1981) wani masanin kimiya ne na Amurka wanda ya lashe kyautar Nobel a Chemistry a shekara ta 1934 saboda gano babban isotope na hydrogen da aka sani da deuterium. Ya ba da gudummawa mai mahimmanci ga fannoni daban-daban, ciki har da atomic da kimiyyar kwayoyin halitta, kimiyyar taurari, da kuma ilimin geochemistry. Urey ya kuma taka muhimmiyar rawa wajen samar da bam din atom a lokacin yakin duniya na biyu kuma ya kasance fitaccen mai ba da shawara kan amfani da makamashin atomic cikin lumana bayan yakin.