The Shield, shown as a question mark ("?") on the Power Meter, is a recurring power up in the Gradius series, usually being the last power up on the Power Meter. They allow a given ship to absorb projectiles and destroy weak enemies on contact a limited number of times before disappearing.
- Shield: A pair of hex gear-like objects fly in from the right side of the screen to attempt to attach to your ship, providing frontal protection. In Gradius V, each side absorbs fifteen hits and usually shrinks with each hit.
- Force Field: The ship is enveloped in an aura that absorbs hits from all sides. It usually absorbs three hits before disappearing, but some games grant more hits. In Salamander, the Force Field looks like half of a classic Shield. Curiously, a scrapped Pile-Up Field from Gradius III would have allowed the stacking of three Force Fields atop each other.
- Multi-Shield: Each Shield power up bestowed upon the ship places a single gear at one of the four cardinal directions. Seen in Salamander and Life Force.
- Free Shield: Same as the Multi-Shield except the gears fly in from the right, and so can be attached to any part of the ship. Seen in Gradius III and Gradius V.
- Rotating Shield: Two Shield gears at opposite points rotate around the ship rapidly. Seen in Gradius III SNES and Gradius V.
- Reduce: In Gradius III Arcade, this shrinks the ship and the collision hit-box; it can be upgraded once for a smaller size. In Gradius III SNES, this shrinks the ship and absorbs up to two hits like the Force Field, with each hit enlarging the ship towards its normal size. The PS2 and PSP versions of Gradius III Arcade provide a Reduce II shield that mimics this function as well as a version of Reduce I that fits in the "!" exclamation cell.
- Guard: A Gradius Gaiden exclusive that protects top and bottom only from two hits. With this shield active, terrain collision is impossible.
- Limit A spherical shield that grants a few seconds of complete invincibility which even allows the ship to pass through terrain.
- Mega Crush: Generally an exclusive of the "!" exclamation cell in Gradius III, but Gradius V has it as an option for the shield cell. Using the Mega Crush clears the screen of weak enemies and all projectiles, which is essentially like using a Blue Capsule.