Guidina Dal Sasso (born 16 January 1958) is an Italian cross-country skier and mountain runner who competed from 1982 to 2002.

In 1985 she came third in the World Mountain Running Championships, and was a member of the winning team.

Dal Sasso, born in Asiago, also competed in three Winter Olympics, earning her best finish of tenth in the 10 km event at Calgary in 1988.

Her best finish at the FIS Nordic World Ski Championships was seventh in the 20 km event at Oberstdorf in 1987.

Dal Sasso has two children with Ferdinando Longo Borghini: Paolo and Elisa, both are professional cyclists.