Green Stars are the green-colored Power Stars that appear in Super Mario 3D World.
They function similarly to Star Medals from Super Mario 3D Land and share the same sound effects. However, unlike Star Medals, there are courses where there are more than three Green Stars at a time. There are also some Mystery Boxes where Green Stars appear, and the player has a set amount of time to collect them before time runs out. Each Green Star additionally grants the player 4000 points.