RMO
RMO may refer to:

 Racemethorphan
 Rahul Mohindar oscillator
 Regional Mathematical Olympiad, the second stage in India for selection to India's IMO team
 Regimental Medical Officer
 Resident Medical Officer
Rijksmuseum van Oudheden
 RMO (cycling team)
 RMO (Norwegian resistance)
 Rocky Mountain oysters