A paddle is a handheld tool with an elongated handle and a flat, widened distal end (i.e. the blade), used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered watercraft by pushing water in a direction opposite to the direction of travel (i.e. paddling). It is different to an oar (which is similar in shape and performs the same function via rowing) in that the latter is attached to the watercraft via a fulcrum.

However, the term "paddle" can also be used to describe objects of similar shapes or functions:

• A rotating set of paddle boards known as a paddle wheel is used to propel a steamboat (i.e. paddle steamer).
• A number of games (e.g. ping-pong), a "paddle" or "bat" is a small racket used to strike a ball.
• A mixing paddle is an agitator device used to stir and more thoroughly mix separate ingredients within a mixture.
• A spanking paddle is used in corporal punishment, typically to forcefully hit someone (e.g. a juvenile) on the buttocks.