The greens, originally known as the queen's party, were the faction of House Targaryen and their loyalists who supported the ascent of Aegon II as King of the Seven Kingdoms during the Dance of the Dragons and the years that preceded it. They were opposed by the blacks.
Their name derives from a great tournament held in 111 AC at King's Landing on the fifth anniversary of the King Viserys I's marriage to Queen Alicent Hightower, his second wife. At the opening feast, Queen Alicent wore a green gown, whilst Princess Rhaenyra Targaryen, Viserys’s daughter by his first wife, dressed dramatically in Targaryen red and black. Note was taken, and thereafter their respective factions at the royal court imitated the fashions they set - the "queen's party" dressing in green, and the "princess's party" dressing in black. In time, it became the custom to refer each party as simply "the greens" and "the blacks". 
Royal Targaryen Members
- King Aegon II Targaryen, King of the Andals, the Rhoynar and the First Men, Lord of the Seven Kingdoms, Protector of the Realm, rode Sunfyre.
- Queen Helaena Targaryen, rode Dreamfyre.
- Prince Aemond Targaryen, Prince Regent and Protector of the Realm, rode Vhagar.
- Prince Daeron Targaryen, rode Tessarion.
- Prince Jaehaerys Targaryen, bonded with Shrykos.
- Princess Jaehaera Targaryen, bonded with Morghul.
- Prince Maelor Targaryen, possessed a dragon egg.
- Queen Dowager Alicent Hightower
- Ser Otto Hightower, Hand of the King, stripped of office.
- Ser Criston Cole, Lord Commander of the Kingsguard and Hand of the King.
- Ser Tyland Lannister, master of ships, then master of coin.
- Lord Jasper Wylde, master of laws
- Lord Larys Strong, master of whisperers
- Grand Maester Orwyle
Aegon II's Kingsguard
- Lord Unwin Peake, Lord of Starpike
- Lord Owen Fossoway, Lord of Cider Hall
- Ser Hobert Hightower
- Ser Jon Roxton
- Ser Tyler Norcross
- Marq Ambrose
- Richard Rodden
- Lord George Graceford, Lord of Holyhall
- Ser Victor Risley, Knight of Risley Glade
- Lord Leygood
- Three other lords and landed knights, slain during the Second Battle of Tumbleton
Defected to the greens
- Lord Butterwell
- Lord Rosby of Rosby
- Lord Stokeworth of Stokeworth
- Lord Owain Bourney
- Ser Roger Corne
- Hard Hugh Hammer, bonded with Vermithor.
- Ulf the White, bonded with Silverwing.
- Lord Manfryd Mooton, Lord of Maidenpool
- Ser Alfred Broome
- Tom Tanglebeard
- Tom Tangletongue
- Lord Corlys Velaryon, Lord of the Tides and Master of Driftmark
Other notable greens
- Three of the "silent five" of House Velaryon
- Lord Jason Lannister, Lord of Casterly Rock
- Lord Humfrey Lefford, Lord of the Golden Tooth
- Lord Swyft of Cornfield
- Lord Reyne of Castamere
- Ser Adrian Tarbeck
- Ser Clarent Crakehall
- Ser Emory Hill, Bastard of Lannisport
Men from the Reach
- Lord Ormund Hightower, Lord of the Hightower
- Ser Bryndon Hightower
- Ser Roger Corne
- Lord Redwyne of the Arbor
- Lord Grover Tully, Lord of Riverrun
- Ser Simon Strong, Castellan of Harrenhal
- Lord Humfrey Bracken, Lord of Stone Hedge
- Ser Amos Bracken
- Ser Raylon Rivers
- Lord Vance of Atranta
- Alys Rivers