The paddle is an object in Alleyway that is controlled by Mario. The player can move the paddle left and right, across the bottom of the screen, using the . If is held while using the , the paddle's movement becomes slower. The paddle is used to deflect the approaching ball into breakable blocks. The angle of the ball is dependent on how the ball hits the paddle. The ball can also be hit by the sides of the paddle, which may result in the ball deflecting in the same direction while mostly preserving its angle. If the ball fails to bounce off of the paddle and hits the screen's bottom edge, one life is taken away.
If the ball hits the ceiling, the paddle becomes shorter. This can first be observed in Stage 4.
In the beginning of the game, Mario is seen entering the paddle through the sliding trapdoor at the top, while the cover art shows Mario inside the paddle in the cosmos, controlling it, implying that the paddle is some sort of vehicle. The North American box art refers to it as a "spaceship", while Nintendo Power refers to it as a "ship". Mario is also shown leaving the paddle if the player loses all of their lives.