This has started the race to determine who succeeds her as Prime Minister.
As of Sunday (June 2, 2019), about 13 people had declared their interest.
One of such candidates is Sam Gyimah, the current MP for East Surrey and a former minister in the May government.
In an interview on Sky’s Sophy Ridge On Sunday, Gyimah said “I will be joining the contest to be the next Conservative leader and prime minister to broaden the race. There is a wide range of candidates out there but there is a very narrow set of views on Brexit being discussed."
Sam Gyimah is of Ghanaian descent. He was born Samuel Phillip Gyimah to Ghanaian parents at Beaconsfield, Buckinghamshire.
His parents separated when he was 6years. After that, he returned to Ghana with his mother and two other siblings while his father remained in the UK.
Gyimah stayed in Ghana for about 10 years and attended the Achimota School before going black to the UK to his GCSEs and A-levels at Freman College.
After moving to the UK, he attended the Somerville College at the University of Oxford, where he read Politics, Philosophy and Economics, and was elected President of the Oxford Union.
He was employed as an investment banker by Goldman Sachs before he setting his own firm in 2003.
His firm, Clearstone Training and Recruitment Limited folded up in 2007.
In 2010, Gyimah was elected an MP during general elections and he held various positions in David Cameron's government.
Gyimah was appointed a Minister of State for Universities, Science, Research and Innovation in January 2018. He, however, resigned in November 2018 in order to be able to criticise May over her Brexit deal.
If successful, Gyimah who was born on August 10, 1976, will become the first black man to become a UK Prime Minister.