The nautical monument, which recently had its historic time ball restored, is joining famous sites across the world in marking St Patrick's Day.
The event, organised by Tourism Ireland, includes landmarks such as the London Eye, Angel of the North and Battersea Power Station. Further afield Table Mountain in South Africa and the Burj Al Arab in Dubai have been rolling out the green.
Councillor Deidre Brock, Culture and Leisure Convener, said: "I can't wait to see the Nelson Monument garbed in green tonight, I'm sure it will be an unforgettable sight! It's testament to Edinburgh's enviable cultural credentials that one of our most historic and best-loved attractions is linking up with such emblematic locations all over the world for this event."
The Nelson Monument is open to the public throughout the year. Admission £3.