Chansey, known in Japan as Lucky (ラッキー, Rakkī^?), is a Pokémon species in Nintendo and Game Freak's Pokémon franchise. Created by Ken Sugimori, Chansey first appeared in the video games Pokémon Red and Blue and subsequent sequels, later appearing in various merchandise, spinoff titles and animated and printed adaptations of the franchise.

Chansey was one of several different designs conceived by Game Freak's character development team and finalized by Ken Sugimori for the first generation of Pocket Monsters games Red and Green, which were localized outside of Japan as Pokémon Red and Blue. Originally called "Lucky" in Japanese, Nintendo decided to give the various Pokémon species "clever and descriptive names" related to their appearance or features when translating the game for western audiences as a means to make the characters more relatable to American children. While her name was originally to be "Lucky" in English, it was changed to "Chansey", which takes from the word "chance".

Chansey, known as the Egg Pokémon, have pink, egg-shaped bodies. They have hair-like outgrowths on the side of their heads. Chansey have stubby limbs, a short tail, and a pouch that holds an egg. Chansey is a female-only species with no male counterpart. Extremely rare in the wild, Chansey is said to bring happiness to those who are lucky enough to capture it. Chansey lays a new egg every day. The egg is extremely nutritious, tasty and sublime. A kind-hearted and charitable Pokémon, Chansey will share its eggs with injured Pokémon it may come across. Chansey walks carefully to protect its egg from damage but can be startlingly fast when it must run from danger.