The former Ukip leader is to attend the grandstand event in Cleveland, Ohio, next week.
But the Brexit supporting former banker, who played a pivotal role during the EU referendum campaign, has refused to throw his support behind any potential Presidents.
He said: “Having criticised President Obama for getting involved in British politics, I am not about to endorse anybody.
“But I do know a lot of people in the Republican Party, and I’ll be interested to hear what Donald Trump has to say in his big speech.”
Mr Farage, who hit out at Barack Obama after the he urged Britons to stay in the EU, has claimed the President’s comments contributed to the result.
He said: “It backfired. We got an Obama-Brexit bounce, because people do not want foreign leaders telling them how to think and vote.”
Trump is now the Republican party’s presumptive Presidential nominee after his rivals pulled out of the race.
But the billionaire businessman is not favoured by many in the so-called establishment wing of the party.
While President Obama and Democrat nominee Hillary Clinton both backed Britain staying in the EU, Donald Trump came out as a Leave supporter.
Mr Farage declined to reveal who had invited him to the Convention and claimed he will be there purely as an observer.
But the MEP did say it was not Trump who had asked him to go to the four-day event.
The Ukip veteran stepped down as party leader after Britons voted to sever ties with Brussels last month.
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