May said that when she brings the Withdrawal Agreement Bill before parliament early next month, it will come with a new package of measures attached that she hopes can command majority support.
"I still believe there is a majority in parliament to be won for leaving with a deal," May wrote in The Sunday Times newspaper.
MPs have already three times rejected the deal May struck with Brussels, forcing Britain's EU departure date to be pushed back from 29 March to 12 April and again to 31 October.
The bill is needed to ratify the divorce agreement struck with the European Union.
On Thursday, May agreed to set out a timetable for her departure following the vote in the week beginning 3 June, regardless of whether MPs back her deal at the fourth time of asking.