Bedrift O - Trysil
- Opsis AS
- Ola Rundfloen
- Oddvar Knutsen
- Oskars Doniks
- Olav Bø
- Ohbeley Hemstad
- Ola Nymoen
- Oulie Eiendom AS
- Orca Konsult AS
- Orwo Invest AS
- Ola Bekkelund
- Occasio Consulting AS
- Ola Gerhard Sørhuus
- Opus Norway Skjæraasen
- Odd Magne Horten
- Odd Magne Myhre
- Ole Gjermund Nymoen
- Oda Sanaker Invest AS
- Omsorgstjenesten i Trysil
- Oppfølgingsenheten Frisk Trysil AS
- Ole Hallstein Holding AS
- O G Sørhuus AS
- Oddrun Borg Rasmussen
- Olles Adventure4all Monika Anna-Katarina Mathiasson