| Oil and vinegar concoction | 26 |
| Oil and vinegar holder | 22 |
| Oil and vinegar holders | 23 |
| Oil and vinegar, maybe | 22 |
| Oil cartel based in Vienna | 26 |
| Oil cartel's initials | 25 |
| Oil cartel's inits. | 23 |
| Oil cartel's letters | 24 |
| Oil city of west Texas | 22 |
| Oil city on the Caspian | 23 |
| Oil company acquired by BP | 26 |
| Oil company in a 1999 merger | 28 |
| Oil company mercenary? | 22 |
| Oil directly from a well | 24 |
| Oil driller's setup | 23 |
| Oil drilling equipment | 22 |
| Oil field investigation | 23 |
| Oil filter accumulation | 23 |
| Oil fire fighter Red ___ | 24 |
| Oil for the lamps of Roma | 25 |
| Oil from flower petals | 22 |
| Oil from orange blossoms | 24 |
| Oil from orange flowers | 23 |
| Oil giant acquired by BP | 24 |
| Oil giant based in Memphis | 26 |
| Oil giant with HQ in Vienna | 27 |
| Oil low in erucic acid | 22 |
| Oil magnate J. Paul ___ | 23 |
| Oil ministers' grp. | 23 |
| Oil ministers' org. | 23 |
| Oil name from long ago | 22 |
| Oil obtained from flowers | 25 |
| Oil of rose petals, e.g. | 24 |
| Oil of wintergreen is one | 25 |
| Oil of wintergreen source | 25 |
| Oil of wintergreen, e.g. | 24 |
| Oil of ___ (cosmetics brand) | 28 |
| Oil on a wall, for example | 26 |
| Oil or vinegar container | 24 |
| Oil painter's mixture | 25 |
| Oil partner in soapmaking | 25 |
| Oil Patch installation | 22 |
| Oil price-setting grp. | 22 |
| Oil producer's grp. | 23 |
| Oil sources for oil paint | 25 |
| Oil spill-monitoring org. | 25 |
| Oil tycoon Halliburton | 22 |
| Oil used in church rites | 24 |
| Oil well drilling gear | 22 |
| Oil well fire fighter of note | 29 |
| Oil well firefighter of note | 28 |
| Oil well firefighter Red | 24 |
| Oil well firefighter Red ___ | 28 |
| Oil well, for instance | 22 |
| Oil, in mechanic-speak | 22 |
| Oil-burning iron lantern | 24 |
| Oil-catching receptacle | 23 |
| Oil-drilling apparatus | 22 |
| Oil-drilling equipment | 22 |
| Oil-drilling structure | 22 |
| Oil-fire extinguisher Red ___ | 29 |
| Oil-producers' gp. | 22 |
| Oil-producers' org. | 23 |
| Oil-rich African country | 24 |
| Oil-rich Canadian province | 26 |
| Oil-rich non-OPEC nation | 24 |
| Oil-rich ruler, perhaps | 23 |
| Oil-rich South American basin | 29 |
| Oil-well capper Red ___ | 23 |
| Oil-well capper Red _____ | 25 |
| Oil-well firefighter Red | 24 |
| Oil-yielding fruit: Var. | 24 |
| Oil-yielding tree of C.A. | 25 |
| Oil-yielding tropical plant | 27 |
| Oil-yielding tropical tree | 26 |
| Oiler great ___ Tikkanen | 24 |
| Oilers' parent org. | 23 |
| Oilers' Skyreach ______ | 27 |
| Oilers, on NHL scoreboards | 26 |
| Oilman ___ P. Halliburton | 25 |
| Oils of a certain art form | 26 |
| Oils owned by the government? | 29 |
| Oils, ecclesiastically | 22 |
| Oily compound used in dyes | 26 |
| Oily hydrocarbon in petroleum | 29 |
| Oink : pig :: ___ : cow | 23 |
| Ointment of the ancients | 24 |
| Ointment package words | 22 |
| Ointment-yielding plant | 23 |
| Ointments for ducktails? | 24 |
| Ojibwa in a Longfellow poem | 27 |
| OK Cola drinker once, perhaps | 29 |
| OK Corral gunfighter Earp | 25 |
| OK for dieters, in ads | 22 |
| OK for the lactose-intolerant | 29 |
| OK setting in the summer | 24 |
| OK to watch, if mom agrees | 26 |
| OK, on a walkie-talkie | 22 |
| Okanagan's ____ pogo | 24 |
| Okanagan's____ pogo | 23 |