AlphaDream

, or AlphaDream (formerly known as AlphaStar), was a Japanese video game development studio that was responsible for developing games for the Game Boy Color, Game Boy Advance, Nintendo DS, Nintendo 3DS, and Nintendo Switch. AlphaDream developed all five games in the Mario & Luigi series, along with Mario & Luigi: Superstar Saga + Bowser's Minions, which is a remake of the first game in the series, and Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, a remake of the third game in the series. The company's staff included prominent developers from Square Co., such as, who worked on Super Mario RPG: Legend of the Seven Stars.

The company was founded on January 12, 2000, as a second-party developer for Nintendo. AlphaDream's first game,  (Japanese: コトバトル－天外の守人), was released only in Japan for the Game Boy Color on March 9, 2001. AlphaDream's first Mario game, Mario & Luigi: Superstar Saga, draws heavy inspiration from , the company's second RPG game, which includes borrowing the art style, the strong resemblance of some characters (such as Hermie III being based on the Yadotsurī enemy), and similar sound effects. Additionally, some files from Tomato Adventures soundtrack appear unused in Mario & Luigi: Superstar Sagas files.

On October 1, 2019, the company ceased operations immediately after filing for bankruptcy, citing sluggish revenues and the high development costs exceeding overall debt. The final game worked on by AlphaDream was Mario & Sonic at the Olympic Games Tokyo 2020, which was released a month after the company's bankruptcy.