Fritz-X, also known as FX-1400 or SD-1400, was a German air-to-ground guided glide bomb, developed during World War II. It was controlled during its descent by an observer in the parent aircraft passing commands via radio.

It was basically a 1400kg armor-piercing bomb, with small wings and a radio receiver mounted on the tail. Signals received by the control device caused small spoilers on the wings to raise into the airstream, causing trajectory changes.

Development began in 1939, and final trials were completed in 1942 in Italy.

It was an uncommon weapon and didn't have a significant impact on the outcome of the war. Its most notable success was the sinking of the Italian battleship Roma in September of 1943. It took three bombs to send her to the bottom.