Ms Truss will make her first appearance as prime minister in Britain's House of Commons on Wednesday.
Liz Truss has been confirmed as the new leader of Britain's Conservative Party and will be the next UK Prime Minister.
The former Secretary of State for Foreign, Commonwealth and Development Affairs of the United Kingdom beat Rishi Sunak by 81,326 to 60,399.
Opinion polls had put her well ahead of former Chancellor of the Exchequer Rishi Sunak but her approval rating was reported to have been waning in recent weeks.
After two months of political instability and a long drawn out leadership contest, Britain's new prime minister was announced shortly after 12.30pm.
Ms Truss and Mr Sunak were the final two to emerge from an original field of 11 candidates.
The new prime minister will make their first appearance in Britain's House of Commons on Wednesday.