Eamonn O'Brien may refer to:

• Eamonn O'Brien (Gaelic football manager) (born 1960), former manager of Meath
• Eamonn O'Brien (footballer) (born 1990), Irish football midfielder

• Ochojec, Rybnik
• Ocho kandelikas
• Ocho Kandelikas
• Ochopee, FL
• Ochopee post office
• Ochopristis
• Ochotona spanglei
• Ochotona whartoni
• O-chou
• Ochpaniztli
• Ochraceous Attila
• Ochraceous-breasted Flycatcher
• Ochraceous Bulbul
• Ochraceous Pewee
• Ochraceous Piculet
• Ochraceous Wren
• Ochraceus
• Ochracin
• Ochraethes
• Ochraethes brevicornis
• Ochraethes citrinus
• Ochraethes clerinus
• Ochraethes cristoforii
• Ochraethes litura
• Ochraethes nigrescens