The island, with a population of about 1500, has now vaccinated almost 100 percent of its target group.
Stuff reports a national celebration was held on Tuesday to mark the vaccination milestone.
With Pfizer vaccines supplied by New Zealand, Niue began its vaccination programme on June 1 and vaccinated 97 per cent of the eligible population on the first round.
The second round went smoothly and achieved the same results, with vaccinations completed on July 9.
Niue's government is looking to vaccinate those aged 12-15, once it gets the go-ahead from MedSafe.
New Zealand's Minster for Pacific Peoples Aupito William Sio said Niue's achievement is significant, and its residents should be proud.
"I'm excited for them, this is a big deal," Sio said.
He said Niue's example sends a strong message that Premier Dalton Tagelagi, who applied science to his decisions, is a good leader.
Tagelagi, in an earlier interview, said the support for vaccination has been tremendous. Those that chose not to vaccinate did so because of religious reasons.
"This is entirely their choice."