King's Knight (キングスナイト, Kingusu Naito) is a 1986 video game published by Square for the Nintendo Entertainment System (NES) and MSX. It was later re-released for the Wii's Virtual Console in Japan on November 27, 2007 and in North America on March 24, 2008.

Although featuring RPG elements, King's Knight is often incorrectly credited both as an RPG and as Square's first development. It was in fact developed by Workss. It was, however, Square's first North American release under their Redmond subsidiary Squaresoft, and their first release as an independent company. King's Knight saw a second release in 1987 on the NEC PC-8801 and the Sharp X1. These versions of the game were retitled King's Knight Special and released exclusively in Japan.

Nobuo Uematsu provided the musical score for King's Knight. It was Uematsu's fourth work of video game music composition.

King's Knight is a vertically scrolling shooter, where the main objective is to dodge or destroy all onscreen enemies and obstacles. Various items, however, add depth to the game. As any character, the player can collect various power-ups to increase a character's level (maximum of twenty levels per character): as many as seven Jump Increases, seven Speed Increases, three Weapon Increases, and three Shield Increases. There are also Life Ups, which are collected to increase the character's life meter. To balance out the Life Ups, there are also Life Downs. Other onscreen icons can affect the stage, such as hidden cave entrances/exits and a "secret revealer," which reveals hidden stones that block progress. Finally, there are four types of elements to be collected in each level, which are vital to the completion of the last stage. These elements are simply elements A, B, C, and D. Each of these elements corresponds to a certain character:

• Ray Jack the Knight — Ray Jack starts with a speed increase at level 1. With four pieces of element D allocated by the last level, he can momentarily change into Zainen, an invincible winged horse.

• Kaliva the Wizard — Kaliva starts with a jump increase at level 1. With four pieces of element A allocated by the last level, he can cast Naizath to destroy all onscreen enemies.

• Barusa the Monster — Barusa starts with a shield increase at level 1. With four pieces of element C allocated by the last level, he can momentarily change into Cetune, an invincible dragon.

• Toby the Thief — Toby starts with a speed increase at level 1. With four pieces of element B allocated by the last level, he can cast Balbath to destroy stones blocking the path.

Just as each character has a corresponding element type, each character has a corresponding stage:

• Stage 1 — Ray Jack's stage.
• Stage 2 — Kaliva's stage.
• Stage 3 — Barusa's stage.
• Stage 4 — Toby's stage.

Each stage has various power-ups, an element of each type, and a cave. Because caves in any given level always house at least one element type (not to mention various powerups), it is vital that the player finds these. Caves are always hidden and are generally found in the middle of a stage. Caves also have statues that shoot fireballs that are very difficult to dodge, and at the end of each cave is a dragon to fight. Once the dragon is defeated, the player can exit the cave and continue with the level.

After the first four stages are successfully completed, the fifth and final stage must be defeated. This stage is unique for many reasons. First, all the warriors come together and fight cohesively as a group of 4. Each shares the same life meter, movements, and firepower. Because the group of four has only the lead character as active, dodging is very difficult. Formation-changing arrows litter this stage, so that the lead character can be changed. This is important because not only will different characters activate different spells, but different characters are good at defeating certain enemy statues.