Mona Ainu'u is a Niuean politician and Cabinet Minister.

Prior to entering politics, Ainu’u was a journalist with the Broadcasting Corporation of Niue and a Public Relations and Media Officer with the Niuean government. She was also the president of the Niue Island Volleyball Association and a founding member of the Pacific Alliance of Development Journalists.

Ainu’u was first elected to the Niue Assembly in the 2017 Niuean general election, representing the Tuapa constituency. She was subsequently appointed Member Assisting the Minister for Natural Resources and later appointed Minister of Natural Resources in the Cabinet of Dalton Tagelagi.

Ainu’u was re-elected unopposed at the 2023 election and reappointed to Tagelagi's cabinet holding the same portfolios.