The Australian Capital Territory House of Assembly was established by ACT Ordinance No.9 of 1979, under the Seat of Government
(Administration) Act 1910. Sections 1,2,3,5,14 and 15 of the Ordinance came into force on 23 April 1979, the date of notification of the Ordinance in the Commonwealth Gazette (No. S71 of 23 April 1979). The remaining provisions came into operation on 2 June 1979, the date of the first election of members to the House.

The House of Assembly replaced the ACT Legislative Assembly (CA 2027), but no changes were made to the "composition, size of membership or fundamental role" of the Legislative Assembly (Minister for the Capital Territory Press Release, 2 March 1979). The change was essentially one of title only.

The function of the House of Assembly is to "advise the Minister on any matter affecting the Territory, including the making of new ordinances or the repeal or amendment of existing ordinances". (Canberra Times, 3 March 1979, p. 1 ) It has no legal function to make or enact laws. The Minister of State for the Capital Territory may submit to the House for consideration any proposals for the making, amendment or repeal of any ordinance, but there is no legal
requirement for this to be done. The House is bound by Section 52 of the Australian Constitution:

"This Parliament shall, subject to this constitution, have exclusive power to make laws for the peace, order and good Government of the Commonwealth with regard to :-

1) The Seat of Government of the Commonwealth and all places required by the Government for public purpose."

The House has 18 members: 9 from the Division of Fraser and 9 from the Division of Canberra. Members are elected for 3 year terms, using the Australian Senate electoral system. The President of the House, elected by the members , has a casting vote; and questions are resolved in the negative if a vote is tied. Ten members are required for a quorum (ACT Ordinance No. 24 of 1973). Debates are conducted to Parliamentary standards and ACT Ordinance No. 36 of 1974 allows the House to make its own rules and procedure.

The House of Assembly derived from a referendum on self-government for the ACT, held on 25 November 1978 after sustained agitation for constitutional change. The referendum was confined to Capital electors and excluded the Jervis Bay Territory as it
"occupied a special place in the range of the Government's responsibilities and the Government did not consider it appropriate that it should be subject to any self-government arrangements which might be made for the ACT."
(Minister for the Capital Territory Press Release 20 October 1978)
The referendum allowed preferential voting for 2 self-government options and one for no change. The first self-government proposal offered the ACT rights similar to those of the States, except for Health, Education and some functions of the Attorney-General - which would be given after 5 years. The financial basis of this option was not made clear. The second option was for a form of municipal or local government. The third option for retaining the status quo, was strongly supported (63.5%), resulting in the only major change to the Assembly's title.

The first election for the House of Assembly were held on 2 June 1979 and the results were published in Commonwealth Gazette No. S113 of 23 June 1979. The candidates elected to represent the Division of Fraser were:
Peter Vallee
Gregory Gane Cornwell
Harold James Hird
Marcus Laurence Robinson
John Michael Clements
Peter Robertson Christie
Donald Anthony Webb
Ivor Francis Vivian
Thomas Wilbur Washington Pye

The Candidates elected to represent the Division of Canberra were:
Kenneth Robert Doyle
James Willoughby Leedman
Maurene Horder
Elizabeth Grant
Robyn Lyn Walmsley
Paul Russell Whalan
Beverly Mary Evelyn Cains
Gordon John Walsh
James Harold Pead

The first meeting of the House of Assembly was held on 29 June 1979, when Peter Vallee was elected President.