Nick Griffin, 58, who grew up in Llanfair Caereinion in Mid Wales, was declared a persona non grata by the Hungarian Government and issued with entry and residency bans.
The announcement came two days after Budapest expelled James Dowson, another prominent British far-right activist with links to Griffin.
Earlier this year Mr Griffin, who headed the BNP from 1999 to 2014, said he planned to move to Hungary as a "refugee" from western Europe, praising the hardline policies of populist Prime Minister Viktor Orban against asylum-seekers.
He said: "I hope that Hungary, the Hungarian government, the Hungarian people, will welcome people who are genuine refugees from western Europe but keep out the liberals who have brought western Europe to this state in the first place."
Tweeting about the ban on Friday Mr Griffin said he was in the process of appealing.
Griffin made the comments during a Budapest visit for a "Stop Operation Soros!" conference, aimed at halting the pro-refugee activities of Hungarian-born US financier George Soros's Open Society Foundation.
Former BNP member Dowson had been operating a branch of the anti-immigration group Knights Templar International in the Hungarian capital since 2015.
The 52-year-old was expelled because authorities considered him a "national security threat", according to security sources cited in the Hungarian weekly newspaper Magyar Narancs.
He also set up a news agency in Budapest that he said aimed to help Donald Trump win the US election last year.