Monster Hunter Generations is an action role-playing game developed and published by Capcom for the Nintendo 3DS. Announced in May 2015, the game was released in Japan as Monster Hunter X in November 2015 and internationally in July 2016. Like other titles in the Monster Hunter series, players undertake quests that involve hunting large dangerous creatures, either solo or in multiplayer. Major additions in this installment include special attacks, new combat styles, and the ability to play as Felynes who have traditionally only appeared as a companion to the player. Monster Hunter Generations is considered the fourth major portable title in the series, following Monster Hunter Portable 3rd. An expanded version of the game, titled Monster Hunter XX, was announced in October 2016, and was released exclusively in Japan in March 2017. An HD port of the expanded re-release for the Nintendo Switch, titled Monster Hunter Generations Ultimate, was released in Japan in August 2017 followed by a worldwide release in August 2018. The game has sold more than 8 million units worldwide, as of September 2020^[update].

Monster Hunter Generations features gameplay similar to past titles in the series. The player assumes the role of a hunter who embarks on quests to hunt dangerous creatures. A hunter's abilities are determined by the type of armor and weapons that they wear on a quest, as the hunter otherwise has no intrinsic attributes that affect gameplay. All fourteen weapon types from Monster Hunter 4 Ultimate, ranging from swords, hammers, bows, guns, and lances, are included in Monster Hunter Generations, in addition to the new Prowler mode which allows the player to take the role of a Felyne, a sentient cat-like species. Each weapon has different sets of moves and abilities that can be employed while in the field. Armors grant defensive bonuses to physical and elemental damage and can boost specific skills and attack types through base attributes and the addition of special decoration gems and talismans. To make a more powerful hunter that can survive against more dangerous creatures, the player takes materials carved from monsters (either slain or captured via traps), as well as materials gathered from the various fields and purchased in village stores, to craft new armor or to craft and upgrade weapons. Defeating more powerful creatures enables even more potent equipment to be crafted, thus creating a gameplay progress through the game's loot system. New in Generations is the ability to transform armor pieces into new gear similar to weapon upgrade paths by upgrading it with materials from broad categories, like bones or ores, and having the ability to upgrade a weapon directly to a more advanced version without the intermediate upgrade steps.

Monster Hunter Generations features new special moves known as Hunting Arts. These moves require the player to wait for the moves to charge up during the course of a hunt before they can be activated. Once ready, the player can activate them at any time, after which they have to wait for them to charge up again before a second use. The Arts have different effects such as dealing massive damage, providing buffs, or healing allies. The game also introduces a system called "Hunting Styles". This system adds different attack styles for a weapon. Each weapon type in the game will have four distinct forms. The Guild Style is a balanced and basic style akin to combat in previous games of the series. The Striker Style is less technical but emphasises the use of Hunting Arts letting the player set up three special attacks. The Aerial Style specialises in mid-air attacks allowing players to use monsters as a platform which they can propel themselves off. The Adept Style gives players an opportunity to perform powerful counterattacks after successfully evading a monster's attack. Visually, the game's combat has been described as flashier than previous titles.

The game will have four new signature monsters along with a number of past flagship monsters. Included are what are known as Deviant Monsters, previous monsters from other games in the series that have been said to have mutated and evolved into more powerful forms, which on defeat will yield spoils of combat that can be used to craft high-level equipment. The game features four villages which are non-combat areas for getting quests and communicating with non-player characters. Three villages return from previous titles, and a new village called Bherna has been added. The game includes an improved resource gathering system; resource points on the various areas will have more items that can be acquired before they are exhausted and the player only has to hold down a controller button to continue to collect items instead of pressing the button each time, and once per mission, the player can call a Felyne messenger to take one inventory's worth of goods back to a village to store.

Planning for Monster Hunter Generations began during the development of Monster Hunter 4 Ultimate. The game's Japanese title—Monster Hunter X, pronounced as Monster Hunter Cross—originated from the idea of crossing old and new elements of the series in the game. Series executive producer Ryozo Tsujimoto saw that since it had been more than ten years since the beginning of the franchise, they wanted to celebrate the occasion, putting the idea of the game as "a festival feeling, a special event". Game producer, Shintaro Kojima, noted that "the letter X looks like it divides the given space into four… so four hunting styles, four large main monsters, four villages. They’re all crossing." The four flagship monsters featured in this title are Astalos, Gammoth, Mizutsune, and Glavenus.

Originally, Capcom considered adding a new weapon type for Monster Hunter Generations. This would have required a lot of development work, so instead they opted to focus on the concept of a player's "attachment to the weapon". The developers noted how players would develop their own approach to combat, which inspired the idea of the hunting skills and arts as these would further give each player to craft a hunter to their unique play style. However, they still needed to balance the strength and effectiveness of these new arts and skills so that Generations would remain fundamentally a game that required the player to read a monster's actions and make the right moves at the right time, and would keep the animation mechanics found in the main series games. Several features—underwater combat, guild quests, and frenzied monsters—from past titles are omitted in Monster Hunter Generations. Tsujimoto said that this was to emphasize the unique elements of the new title.

As with Monster Hunter 4, Generations includes a number of quests that help to orient a player to the various gameplay systems within the game; this includes special quest lines for each weapon type to help accustom the player to that weapon and its strategies. The Prowler-Felyne hunter choice was aimed specifically for new players of the series, but also to give veteran players a new way to experience the title. With the Prowler mode, it helps to emphasise the need to watch the monsters and read their tell before making a move and gaining the opportunity for a counterattack.

While the period between the Japanese release of Monster Hunter 4 and Generations was nearly annual, the producers state they have no expectations to make Monster Hunter an annual series. They found the response from Western audiences with these two games overwhelming, and are working to make the localization process easier to reduce the time between the Japanese and Western releases, and would like to eventually see a simultaneous release in these regions in the future.