Labels which are indented have no illustrations.
Label scans which have been sent in to this site have often been been given black vinyl 'surrounds' to make them match the others; therefore singles which are shown with a serrated ridge around the label may not actually have had that ridge.

OAK
OASIS
OATS
OBJECT MUSIC
OBLIQUE
OBLIVION
OBM
OCEAN (OC prefix)
OCEAN (OCS prefix)
OCR
OCTANE
ODDBALL PRODUCTIONS
ODE
ODEON
ODEON (ODN prefix)
OHM
O.H.M...S
OILY
OK (DIY)
OK (Scottish)
OLD GOLD
OLD KNEW WAVE
OLYMPIC (MOR prefix)
OLYMPIC (OR prefix)
OMNIA
100 PIPERS
194 RADIO FORTH
ONE OFF RECORDS
1 OFF (Stiff)
1 STOP
1 TRACK
ONE WAY (Reggae)
ONE WAY (Punk)
OPAL
OPEN UNIVERSITY
OPTIMISTIC
OR
ORANGE
ORANGE PEAL - see IAL
ORBITONE
ORCHID
ORGANISATION
ORK
ORPHAN
OSPREY
O'SULLIVAN
OTHER
021
OUR OWN
OUTATUNE
OUTER HIMMILAYAN
OUTLAW
OUT OF THE PAST
OUTLET
OUTPUT
OUT TO LUNCH
OVAL
OVALSTIFF
OVATION
OVEGBATA / OYEGBATA
OVEN READY
OVERDRIVE
OXFORD UNIVERSITY PRESS
OYEGBATA / OVEGBATA
OYSTER
OZARK