The National University of Ireland, Maynooth, commonly known as Maynooth University (MU), is a constituent university of the National University of Ireland in Maynooth, County Kildare, Ireland. It was Ireland's youngest university until Technological University Dublin was established in 2019, as it was founded by the Universities Act, 1997 from the secular faculties of the now separate St Patrick's College, Maynooth, which was founded in 1795. Maynooth is also the only university town in Ireland, all other universities being based within cities.

With over 13,000 students enrolled, and over 900 staff from over 20 different countries, it is Ireland's smallest, yet fastest growing, university. In 2009, Maynooth University was listed as a Top500 university in the Times Higher Education-QS World University Rankings. The 2012 QS World University Rankings put MU in the 501–550 bracket worldwide, but most recently, Maynooth University was ranked in the 701–750 bracket in the 2019 QS World University Rankings. In 2008 it was named Sunday Times 'University of the Year'. In 2011, Maynooth University became the first and only institution outside of North America to be included in The Princeton Review of Best Colleges. It also has the highest proportion of university participation in Ireland of mature students (16%) and access students (22%).