A fluid funnel includes an open-topped mouth for receiving DEF or other liquids from a jug or other source; an elongated hollow stem depending from the mouth for directing the fluids from the mouth into a DEF tank or other fluid receptacle; and a tapered throat that joins the mouth and stem. The funnel more effectively direct fluids into a tank, even when the funnel is tilted; inhibits fluids from backing-up into the mouth and/or spilling out of the funnel; prevents displaced air from bubbling up through fluids in the mouth; and more firmly engages and seats within a tank port.