“If a vote was to come up, I would do what I did last time round which was sit down and look carefully at the issues,” she told the France 2 TV channel.
“But there isn’t going to be another vote, so this is not an issue. What is going to happen is the UK is going to leave the European Union. There will be no second referendum on Brexit. We took the decision as a parliament that the British people should have their choice.”
The Prime Minister, campaigned for Remain during last year's vote and has subsequently overseen the triggering of Article 50 - the start of two years of negotiations to thrash out a deal for Britain's exit from the EU.
It means that the UK will quit the EU by March 29 2019 at the latest, ahead of the European Parliament elections in May of that year.
The Prime Minister was criticised when she made similar comments in October 2017 when she again refused to say how she would vote in a second referendum.
Pressed for an answer on LBC radio, Ms May said: “I could say I would still vote Remain or I would vote Leave just to give you an answer to that question. I am being open and honest with you.
“What I did last time round was I looked at everything and came to a judgement and I’d do exactly the same this time round.
“But we are not having another referendum and that’s absolutely crucial.”
Shortly afterwards Jeremy Corbyn has said he would vote Remain again in a further referendum.
The Labour leader said: “I thought the best option was to remain, I haven’t changed my mind on that.”