Zelda II: The Adventure of Link is a 1987 action role-playing game developed and published by Nintendo. It is the second installment in the Legend of Zelda series, and was released in Japan for the Famicom Disk System on January 14, 1987, less than a year after the Japanese release and seven months before the North American release of the original The Legend of Zelda. Zelda II was released in North America and the PAL region for the Nintendo Entertainment System in late 1988, almost two years after its initial release in Japan.

The Adventure of Link is a direct sequel to the original The Legend of Zelda, again involving the protagonist Link, on a quest to save Princess Zelda, who has fallen under a sleeping spell. The game's emphasis on side-scrolling platform and role-playing elements marked a significant departure from its top-down predecessor.

The game was a critical and commercial success, and introduced elements such as Link's "magic meter" and the Dark Link character that would become commonplace in future Zelda games; however, the role-playing elements, such as experience points and limited lives, have not been used since in canonical games. The Adventure of Link was followed by A Link to the Past for the Super Nintendo Entertainment System in 1991.

Zelda II: The Adventure of Link is an action role-playing game that bears little resemblance to the first or later entries in the Legend of Zelda series. It features side-scrolling areas within a larger top-down world map, unlike the exclusively top-down perspective of the first game. The side-scrolling gameplay and experience system are similar to features of Konami's Castlevania series, especially Castlevania II: Simon's Quest. The game incorporates a strategic combat system, a proximity continue system based on lives, an experience points system, magic spells, and more interaction with non-player characters. Apart from the non-canonical CD-i The Legend of Zelda games, Link: The Faces of Evil and Zelda: The Wand of Gamelon, no other game in the series includes a lives feature. The side-scrolling perspective is used in a minor capacity in Link's Awakening and the other Game Boy entries, while the top-down perspective still takes focus.

In this installment, Link gains experience points to upgrade his Attack, Magic, and Life attributes by defeating enemies. He can raise each of these attributes a maximum of seven levels above their starting point. A level increase for Attack, Magic, or Life will respectively increase the sword's offensive power, decrease the amount of magic needed to cast spells, and reduce the damage Link takes from enemy attacks.

In the Western version of the game, each attribute requires a different amount of experience to level up, with Life requiring the fewest points to level and Attack requiring the most. When enough points are acquired to raise an attribute, the player may choose to level up that attribute or to cancel and continue gaining experience points towards the next level in another attribute. In the original Japanese version, all attributes require the same number of experience points to level up, and the required number is lower; however, if the player loses all lives, the levels of all attributes will be reset to the lowest of the three (while level upgrades in the Western version are permanent). Once Link has raised an attribute to the maximum level of eight, further advances in that attribute will earn Link an extra life, without advancing the attribute itself. Link begins the game with four Heart Containers and four Magic Containers and can acquire up to four more of each, permanently increasing his life points and magic points respectively. Other games in The Legend of Zelda series only allow Link to increase his strength through new weapons, items, and Heart Containers. Certain enemies drain Link's experience when they attack, but he will never lose a level once raised. When a game ends or is saved, the cartridge records Link's current ability levels and the number of experience points required for the next increase but resets his accumulated points to zero.

The Adventure of Link has a dual-mode dynamic of top-down view and side-scrolling view. This duality of either traveling or entering combat is one of many aspects adapted from the role-playing genre. The overworld, the area where the majority of the action occurs in other Zelda games, has a top-down perspective, but it now serves as a navigational map to the other areas. While traversing Hyrule, figures randomly appear around the player: a small blob denoting easy enemies, a large biped denoting harder enemies, and a Fairy to refill Link's health. The game switches to side-scrolling mode when Link steps onto particular spots in the overworld map to enter towns, buildings, or caves, or when he encounters wandering monsters. This mode has most of the action and danger.

The Adventure of Link has a more complex combat system than its predecessor. Armed with a sword and shield, Link must alternate between standing and crouching positions to attack enemies and defend himself; for example, the Iron Knuckle enemy changes the height of its attack and its shield depending on Link's current stance, forcing Link to change stances until he has a chance to attack safely. Link has the ability to jump, which can be used for attacking tall or airborne enemies and can be used for evasion. Eventually, he can learn techniques for midair downward and upward stabs.