Sumie Inagaki (?????, Inagaki Sumie, born 6 April 1966) is a Japanese ultramarathon runner from Hokkaido.
Inagaki holds current women's world record in 24-hour run Indoor (240.631 kilometres (149.521 mi), Espoo FIN, Jan 2011), and in 48-hour run Track (397.103 kilometres (246.748 mi), Surgeres FRA, May 2010).
She is a two time female winner of IAU 24-Hour Run World Championship.
She was the female winner of 2006 and 2009 Spartathlon, and the female winner of 2011 and 2012 Badwater Ultramarathon.