Urusei Yatsura 2: Beautiful Dreamer is a 1984 Japanese animated fantasy comedy film produced by Kitty Films and distributed by Toho. It is the second film in the Urusei Yatsura film series based on the manga of the same name by Rumiko Takahashi. In the film, a group of Japanese high school students including Lum and Ataru prepare for the annual school cultural festival and begin to question the reality around them after a series of perplexing events. The film experimented with concepts such as a time loop, dreams, and simulated reality, in departure from the previous film Only You which was more faithful to Takahashi's original manga and anime series.

The film was written and directed by Mamoru Oshii with Yuji Moriyama as animation director. Its predecessor, Only You, was also directed by Oshii. Beautiful Dreamer was a significant departure, with Oshii placing an emphasis on philosophical issues.

Although the film received mixed responses upon its initial release, Beautiful Dreamer later received critical acclaim as an early example of Oshii’s style of filmmaking. The film was ranked among the best Japanese animated films of all time, including film magazine Kinema Junpo. The film has drawn comparisons to later works including Oshii's directed Ghost in the Shell (1995), Groundhog Day (1993), Dark City (1998), and Inception (2010).