They fight evil with the aid of rings that grant them a variety of extraordinary powers, all of which come from imagination and/or emotions. Green Lantern Corps, an interstellar law enforcement agency.

The ring is powered by willpower. Each Green Lantern wears a ring that grants them a variety of possibilities. The full extent of the ring's ability has never been rigorously defined in the stories, but two consistent traits are that it grants the power of flight and that all its effects are accompanied by a green light.

Early Green Lantern stories showed the characters performing all sorts of feats with the ring, from shrinking objects to turning people invisible. Later stories de-emphasized these abilities in favor of constructs.

The signature power of all Green Lanterns is the ability to conjure constructs: solid green objects that the Green Lantern can control telekinetically. These can be anything, such as a disembodied fist to beat a foe, a shield to block an attack, a sword to cut a rope, or chains to bind a prisoner. Whatever their shape or size, these constructs are always pure green in color, unless a Lantern is skillful enough to know how to change the EM spectrum the construct emits. Hal Jordan has shown the ability to have a construct emit kryptonite radiation under Batman's guidance.

Green Lantern is famous for the oath he recites when he charges his ring. Originally, the oath was:

In brightest day, in blackest night,No evil shall escape my sight!Let those who worship evil's mightBeware my power, Green Lantern's light!