In the 1918 General Election women were nominated as Parliamentary candidates for the first time. There were seventeen women candidates in Britain, but only one stood for a Welsh constituency, namely Millicent Mackenzie (Labour) for the University of Wales seat. There were three female candidates in the 1922 General Election, but only one by 1924.

The first successful female candidate was Megan Lloyd George who won the Anglesey seat for the Liberal Party in 1929. She held on to the seat until 1951, and later became Labour MP for Carmarthen from 1957 to 1966.

The number of women parliamentary candidates rose from 67 to 87 in the 1945 General Election, but there were still only three in Wales.

The 1950 General Election was a great success for Welsh female candidates, with three of the four female candidates winning a seat. Eirene White became Labour MP for East Flint after gaining 48.5% of the vote; Megan Lloyd George's majority increased in Anglesey; and Dorothy Rees won the Barry seat for the Labour Party with a majority of 1,025 votes. For the first time in Wales, the Communist Party had a female candidate, M. Llewellyn, who came third place in Ogmore that year.

In the 1951 General Election Megan Lloyd George lost her seat to Cledwyn Hughes in Anglesey by 595 votes; Dorothy Rees lost her seat in Barry and Josephine Richardson was unsuccessful in Monmouth. Eirene White kept her seat in East Flint with 53.8% of the vote.

Two women competed for the same seat for the first time in the Carmarthen by-election of 1957. Megan Lloyd George (Labour) won, and Jennie Eirian Davies (Plaid Cymru) came third with 5741 votes. Only four women stood for parliamentary seats in the 1966 General Election, including Jenny Gibbs the unsuccesful Liberal candidate for Ogmore.

The number of female MPs increased slowly over the years. Beata Brookes, Ann Clwyd, Glenys Kinnock and Eluned Morgan became MEPs, and Julie Morgan, Jackie Lawrence and Betty Williams became MPs. For the 1999 Welsh Assembly Election, Plaid Cymru and the Labour Party purposely attempted to recruit equal numbers of male and female candidates. This ensured that as many as 40% of today's Assembly Members are female