All terms alphabetically ordered
- Occupational diseases
- Occupational therapy (Daily structure for persons with disabilities)
- Offenders' assistance (Discharge from prison)
- Office of inland revenue (Tax office)
- Ombudsman
- Ombudsman public (Attorney of the people)
- Online counselling
- Orthopaedic aids (Technical aids for persons with physical disability)
- Orthoptics (Squinting)
- Over-night shelters (Emergency accommodation for homeless persons)
- Oxygen service