The history of policing in Western Australia began with the founding of the colony in 1829 when Governor Stirling appointed a few part-time constables to maintain public order in Perth and Fremantle. A troop of Mounted Police was formed in 1834 and other types of police were added as the needs of the colony changed, particularly after the introduction of convicts. The colony's Legislative Council passed a Police Ordinance in 1849 that outlined police powers and responsibilities. An organised Police Force did not as yet exist. The force was formally established in 1853, when a Chief of Police was appointed and a Code of Rules published outlining an administrative structure.

In 1861, a second and expanded Police Ordinance was passed to clarify the chain of command, the powers and responsibilities of members and the various offences they had to deal with. In that year, the force consisted of about 75 commissioned officers and men. The extent of police jurisdiction expanded with the State, and by the time the Police Act of 1892 - still largely in force - was passed, the number of members had increased three-fold. Until the era of Commissioner Robert Connell, who took rein in 1912, the management of the police was largely in the hands of colonial gentry, former military men and public servants.

Mission:
To preserve the peace within the community of Western Australia.

Functions:
To protect life and property;
To prevent crime or detect and prosecute offenders against those laws which confer duties, powers or authority upon members of the Western Australia Police Force.

The Western Australia Police Department changed its name to that of Western Australian Police Service in May 1995.

The Authority was formed to ensure enforcement of the various Acts and Regulations in respect to traffic and facilitate and maintain a licensing system for vehicles and motor drivers. The Authority was further charged with research into traffic accidents, the collection and analysis of statistics, publication of information and advice of a general or technical nature, investigation of laws relating to traffic and most significantly "... the attaining of the continuous co-operation and support of the community in achieving higher standards of road safety and more efficient traffic movement" (Road Traffic Authority Annual Report 1975).

The Western Australian Police Department changed its name to that of Western Australia Police Service in May 1995.

Commissioner Dr Karl O'Callaghan initiated a subsequent name change in 2005 to the Western Australia Police.