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