25th Anniversary Celebration (released in Japan as Altan: With the RTÉ Concert Orchestra) is the tenth studio album by Irish folk music group Altan.

The album does not contain new original material (except for one new song, "Soilse na Nollag") for it is a compilation of studio re-recordings of previous material with orchestral arrangements.

25th Anniversary Celebration was recorded in the RTÉ studios, Dublin, Ireland with the contribution of the RTÉ Concert Orchestra.

The album was released on 31 January 2010 in Japan (where it had its launch in December 2009 during Altan's Winter 2009 Japanese tour) and on 2 March 2010 in North America.

The late Proinsias Ó Maonaigh (Francie Mooney) was Mairéad Ní Mhaonaigh's father.