Young-adult fiction or young adult literature (often abbreviated as YA), also juvenile fiction, is fiction written, published, or marketed to adolescents and young adults. The Young Adult Library Services (YALSA) of the American Library Association (ALA) defines a young adult as someone between the ages of twelve and eighteen. Authors and readers of young adult (YA) novels often define the genre as literature as traditionally written for ages ranging from twelve years up to the age of eighteen, while some publishers may market young adult literature to as low as age ten or as high as age twenty-five. The terms young-adult novel, juvenile novel, young-adult book, etc. refer to the works in the YA category.

Ungdomslitteratur är skönlitteratur med ungdomar som målgrupp, det vill säga ungefär åldrarna 12 till 18 år.

Nuortenkirjallisuudeksi kutsutaan kirjallisuutta tai teoksia, jonka kohderyhmäksi on rajattu nuoriso. Genre rinnastetaan monesti lastenkirjallisuuteen, jolloin siitä puhutaan lasten- ja nuortenkirjallisuutena.