Orsa or ORSA may refer to:
Places: Orsha or Orša, Belarus Orsa, Sweden Orsa Municipality, Swedish municipality
Vessels: Orsa-class torpedo boat, built for the Italian Navy in the 1930s Italian training ship Orsa Maggiore (A5323), a contemporary ocean ketch serving as a sail training vessel
Other uses: Orsa (moth), a moth in the family Erebidae Operations Research Society of America Own Risk and Solvency Assessment, in EU insurance regulation Oxacillin-resistant Staphylococcus aureus