Ms. Truss saw off the challenge of former Chancellor of the Exchequer, Rishi Sunak, to become the new leader of the Conservatives.
She received 57.4%, 81,32, of the votes to Rishi Sunak’s 42.6%, which was 60,399.
Ms. Truss becomes only the third female Prime Minister in UK history.
The decision brings to an end a long process which was triggered back in July when prime minister Boris Johnson announced his resignation.
Truss has immediate challenges ahead, with the most pressing being the spiralling cost of energy which is already affecting millions in the UK.
Who is Liz Truss?
Liz Truss, whose real name is Mary Elizabeth Truss, was born in Oxford on 26 July 1974. She has held several cabinet positions including Secretary of State for International Affairs and Secretary of State for Foreign, Commonwealth and Development Affairs.
She has also been the Member of Parliament for South West Norfolk since 2010.
Her time as Foreign Secretary has seen her front and centre of the UK’s response to the ongoing Russian invasion of Ukraine which started back in February 2022.
She gained enough support from within the party to reach the final two of the decision process, of which she came out victorious against Rishi Sunak.
Truss campaigned for the UK to remain inside the European Union in the run-up to the Brexit referendum in 2016.
Who is her husband and does she have children?
Liz Truss has been married to accountant Hugh O’Leary since 2000. The couple have two children.
What did Liz Truss say about the cost of living crisis?
Truss announced on Sunday that she would provide a plan to tackle the energy crisis within a week of becoming Prime Minister.
Speaking on BBC One’s Sunday with Laura Kuenssberg, Liz Truss said that it is “vital” that action is taken on rising energy bills.
Upon being elected as prime minister, Ms. Truss said: “I will deliver on the energy crisis dealing with people’s energy bills, but also dealing with the long term issues we have on energy supply.”
Will there be an emergency budget?
Liz Truss also announced on the show that should she win, she promised to deliver around £30 billion in tax cuts as part of an emergency budget later in September.
She was pressed over who would be impacted most by the tax cuts, adding that “growing the economy benefits everyone.
"The people at the top of the income distribution pay more tax - so inevitably, when you cut taxes you tend to benefit people who are more likely to pay tax.
"To look at everything through the lens of redistribution I believe is wrong. Because what I’m about is growing the economy - and growing the economy benefits everybody.”
What has Liz Truss pledged to do as Prime Minister?
Liz Truss has backed herself to lead the country by growing the economy and level up the entirety of the UK.
In her leadership bid statement, she said: “I am the candidate with a clear vision based on our shared Conservative principles of low tax, freedom and sound economic management.
“We must grow the economy, level up across our United Kingdom and fight for freedom at home and across the world.
“Now is the time to deliver.
“I have a track record of delivery across government. As your Prime Minister, I will lead a Government that puts money back in your pocket, and secures a better future for you and your family.
“These are serious times. I have the experience, vision and strength that is needed.”