O
- Object of federal/ regional/ local level (importance) (Russia)
- object of national importance (Estonia)
- object of significant spatial impact (Estonia)
- Objection (Finland)
- objection (Denmark)
- objection (Estonia)
- Objectives in land use planning (Finland)
- Objects of spatial planning (Belarus)
- off-shore installation (Latvia)
- one-family dwelling (Estonia)
- online publication (Latvia)
- open land (Latvia)
- Open space (Russia)
- open space (Denmark)
- open space (Latvia)
- open space planning (Germany)
- open-space structure (Germany)
- Opinion, statement, comment (Finland)
- Order of the Strategic Impact Assessment of Plans and Programmes (Lithuania)
- ordinance (Germany)
- organic agriculture (farming) (Latvia)
- Organiser's attorney of planning (Lithuania)
- Organisers of detailed planning (Lithuania)
- Original property unit principle (Finland)
- Out-door life (Norway)
- Outbuilding (Finland)
- outbuilding (Estonia)
- Outdoor recreation (Sweden)
- Outdoor Recreation Act (Norway)
- Outdoor Recreation Act (Finland)
- Outdoor recreation route (Finland)
- Outline plan, disposition plan (Finland)
- outside (opened) storage (Latvia)
- Overall Dimension of an Object (Poland)
- Overall plan (Norway)
- owner of land (Estonia)
- Owner, developer (Sweden)

Belarus
Denmark
Estonia
Finland
Germany
Latvia
Lithuania
Norway
Poland
Russia
Sweden

