The Abu Dhabi Media Office said the drone hit an electrical generator outside the inner perimeter of the Barakah nuclear power plant in the Al Dhafra region.
"No injuries were reported, and there was no impact on radiological safety levels," it added.
The Federal Authority for Nuclear Regulation confirmed that the plant's essential systems were operating normally.
There was no claim of responsibility for the strike, and UAE authorities also did not blame any party for the attack.
It is the first time the four-reactor Barakah plant has been targeted in the Iran war. The facility is the only nuclear power plant on the Arabian Peninsula.
Sunday's strike comes amid a fragile ceasefire in the conflict between the US and Iran.
UAE warns drone attack 'a dangerous escalation'
The defense ministry of the United Arab Emirates (UAE) said that the drone that hit an electrical generator at Barakah Nuclear Power Plant was one of three that had crossed the country's western border.
"Investigations are underway to determine the source of the attacks," the ministry said in a statement, adding that the incident represented a "dangerous escalation."
"The Ministry of Defense announced that on 17th May 2026, UAE air defense systems intercepted three UAVs that entered the country from the western border direction," it said.
"Two were successfully intercepted while the third struck an electrical generator outside the inner perimeter of the Barakah Nuclear Power Plant in the Al Dhafra area."
The UAE emphasized that it would not tolerate any threat to its security and sovereignty "under any circumstances."
UN watchdog voices 'grave concern' over strike near UAE nuclear plant
The UN nuclear watchdog said it was "following the situation closely" at Abu Dhabi's Barakah nuclear power plant after a drone strike caused a fire at the site's perimeter.
"Emergency diesel generators are currently providing power to the (nuclear power plant's) unit 3," the Vienna-based International Atomic Energy Agency (IAEA) said on X.
"The IAEA is following the situation closely and is in constant contact with the UAE authorities, ready to provide assistance if needed," it added.
It went on to say that IAEA head Rafael Grossi "expresses grave concern about the incident and says military activity that threatens nuclear safety is unacceptable."
Grossi also called for "maximum military restraint" near nuclear power plants to avoid the danger of a nuclear accident, the X post said.