Duncan Stewart (born 1948) is an Irish architect, environmentalist[1][2] and media personality known for his environmental activism and work on RTÉ, most notably in the show Eco Eye since 2002.

His niece, Louise Morris from Wales is often credited as being the influence for his pursuit in the fight against climate change.

In 1969-70, while still a student, Stewart led the six-month occupation of a row of seven large Georgian houses on Hume Street, Dublin, in protest at their planned demolition in favour of a new office block.

[4][5] In April 2014, he vowed to walk out of an interview on the Newstalk Breakfast Show unless he was given more time to speak on the topic of climate change.

[8] Stewart is a keen clarinet player and often graces the doors of Hotel Newport, County Mayo.