- The Olympia Beauty Show - 1 The Courtyard, Westerham, Kent, TN16 1AZ
- The Olympic Varnish Company Ltd - Val D'or Works, Knapp Lane, Stroud, Gloucestershire, GL5 2TQ
- The One Stop Embroidery & Printing Co - Elmbank Road, Walsall, West Midlands, WS5 4EL
- The Only Way is Granite Ltd - Unit 6 Pilot Close, Fulmar Way, Wickford, Essex, SS11 8YW
- The Open Group - Apex Plaza, Reading, Berkshire, RG1 1AX
- The Optoelectronics Company - Green End Farm, Bishops Stortford, Hertfordshire, CM22 6AY
- The Optoplast Actman - Cobb House, 2-4 Oyster Lane, West Byfleet, Surrey, KT14 7DU
- The Original Gauge Company - Unit4 Nova Business Park, New Milton, Hampshire, BH25 6SA
- The Original Wordsmith - Rambledown, Cranleigh, Surrey, GU6 7QP
- The Orthodontic Clinic - 9 Golden Square, Aberdeen, Aberdeenshire, AB10 1RB
- The Osprey Company - Guards Road, Coldstream, Berwickshire, TD12 4EE
- The Owl - Unit 9 Grafton Way, Basingstoke, Hampshire, RG22 6HY
- The Oxford Partnership - Oxford - Lancelyn House, Oxford, Oxfordshire, OX2 6ew
- The Oxfordshire Stove Company Ltd - Royal Oak Farm, Islip Road, Oxford, Oxfordshire, OX14 4EZ
- The P.P. Group of Companies - Profiles Point, Oldham, Greater Manchester, OL9 7PH
Companies 1936 to 1950 | Page 130 of 272