| Oaths, Affidavits and Statutory Declarations Act 2005 | 023 of 2005 |  |  |  |
| Occupational Health, Safety and Welfare Act 1984 | 101 of 1984 | | | |
| Occupational Safety and Health Act 1984 | 101 of 1984 | | | |
| Occupiers' Liability Act 1985 | 052 of 1985 | | | |
| Offenders (Legal Action) Act 2000 | 046 of 2000 | | | |
| Official Prosecutions (Accused's Costs) Act 1973 | 046 of 1973 | | | |
| Official Prosecutions (Defendants' Costs) Act 1973 | 046 of 1973 | | | |
| Off-shore (Application of Laws) Act 1982 | 021 of 1982 | | | |
| Offshore Minerals (Registration Fees) Act 2003 | 011 of 2003 | | | |
| Offshore Minerals Act 2003 | 010 of 2003 | | | |
| Oil Refinery (Kwinana) Agreement Act 1952 | 001 of 1952 (1 Eliz. II No. 1) | | | |
| Oil Refinery Industry (Anglo-Iranian Oil Company Limited) Act 1952 | 001 of 1952 (1 Eliz. II No. 1) | | | |
| Onslow Solar Salt Agreement Act 1992 | 050 of 1992 | | | |
| Ord River Dam Catchment Area (Straying Cattle) Act 1967 | 036 of 1967 | | | |
| Ord River Hydro Energy Project Agreement Act 1994 | 076 of 1994 | | | |
| Owner-Drivers (Contracts and Disputes) Act 2007 | 007 of 2007 | | | |
