- Olopen
- OLP
- OLR
- Olsztyn
- OLTP
- Oluanpi
- Olufemi Obafemi
- O. Lummer
- O. Lummer, 1860—1925
- olymer chelating agent
- Olympia
- Olympiad
- olympiadane
- Olympiastadion Berlin
- Olympic anthem
- Olympic Arts Festival
- Olympic bidding city
- Olympic capital
- Olympic Charter
- Olympic coins
- Olympic commemorative pins
- Olympic Council of Asia
- Olympic Cup
- Olympic dam copper-uranium-gold deposit
- Olympic Day