She said only her party had the "legitimacy" to govern after winning the most seats and votes.
In a short statement outside Downing Street after an audience with the Queen, Mrs May said she would join with her DUP friends to get to work on Brexit. Speaking of the coalition with the DUP, May said that the two parties had "enjoyed a strong relationship over many years" - and that she would pull Britain together "to secure a successful Brexit deal that works for everyone".
It not known yet what sort of deal will be formed between both parties as the choice ranges from a formal coalition or an arrangement, known as "confidence and supply", where the DUP will support the Conservatives' minority government on important matters in return for some of their policies being enacted.
The Tories remain the biggest party with 318 seats and Labour has 262 - with 326 required for a majority.
May met stiff competition from her rival Jeremy Corbyn of the opposition Labour Party, who garnered 261 seats in the election, a gain of 29.
Although the DUP backed Brexit, its leader Arlene Foster has spoken against a "hard Brexit" and against a hard border with the Republic of Ireland where people and goods would be subject to checkpoints.
Prominent members of the party have repeatedly been quoted referring to homosexuality as an "abomination.' The DUP's Jim Wells resigned from his position as Health Minister in 2015 after suggesting that a child brought up in a 'homosexual relationship" would be 'far more likely to be abused and neglected'.
She explained that her government will seek to lead the country through Brexit negotiations, rejecting speculation she will delay negotiations on leaving the European Union which begin in ten days' time.
With the DUP providing the Conservatives a narrow, but crucial, majority in Parliament, it could have an outsized influence.
In 2016, DUP leader Arlene Foster said: "I would not want abortion to be as freely available here as it is in England".
A "civil service reform plan" would be a key feature of the long-term, cross-government vision - which the party said needed measurable targets and agreed dates. Most of the time, a traveller barely sees a sign noting the change in countries.
"It's an issue very close to my heart and one that I wanted categoric assurances from the prime minister on, and I received (them)".
It is understood that the DUP has committed to supporting the Conservative Party in principle.
In the aftermath of the vote to leave the European bloc, DUP politicos have pushed for a kinder, gentler Brexit, and one that takes into account the unique history and geography of Ireland.
It will be hard for the UK Government to be seen as a neutral arbiter in Northern Ireland when the DUP is propping up the Conservatives in office.