May outlined plans to set the UK's departure date and time from the EU in law, warning she will not tolerate any attempt to block Brexit.
"Let no one doubt our determination or question our resolve, Brexit is happening," she wrote in an article in The Daily Telegraph.
"It will be there in black and white on the front page of this historic piece of legislation: the United Kingdom will be leaving the EU on March 29, 2019 at 11 p.m."
The draft legislation has already passed its second reading and will now be scrutinised by MPs next week, reports the BBC.
May said most people wanted politicians to "come together" to negotiate a good Brexit deal, adding that MPs on all sides should help scrutinise it.
She said the government would listen to MPs if they had ideas for improving the bill but warned against attempts to halt the process.
"We will not tolerate attempts from any quarter to use the process of amendments to this Bill as a mechanism to try to block the democratic wishes of the British people by attempting to slow down or stop our departure from the European Union."
May said the "historic" bill was "fundamental to delivering a smooth and orderly Brexit" and would give "the greatest possible clarity and certainty for all businesses and families across the country".
Negotiations between London and Brussels have entered their sixth round without any progress on the terms of the UK's departure from EU, a deadlock that has created great uncertainty for companies and EU citizens living in the UK.