The discovery of a very high velocity, low-intensity gas feature in the giant extragalactic H II region NGC 5471 is reported. A broad component in the emission lines of H-alpha + forbidden N II 6548, 6584 A is located within an area less than 1 arcsec in diameter at the position known as knot C. The broad component is characterized by its low intensity, a contribution of roughly 25 percent to the total flux of the lines, and an extension of roughly 3300 km/s at full width at zero intensity (FWZI). Supernovae explosions and stellar winds are considered as possible sources of the gas motions, and the observational evidence for their presence is discussed.