Schmitt, who was elected to his largely ceremonial office in 2010 for a five-year term, said in a speech at the start of parliament's plenary session that he was stepping down because his "personal issue" was dividing Hungary.
His 1992 doctorate was revoked last week after an investigation at Budapest's Semmelweis University found that most of his thesis about the modern Olympic Games had been copied from the work of two other authors.
Soon after Schmitt spoke, Hungary's governing Fidesz party said it planned to have parliament vote later on Monday to accept the resignation and to have the legislators choose his successor as soon as possible.
