Seinen manga (青年漫画^?) is a subset of manga that is generally targeted at a 18–30 year old male audience, but the audience can be older with some manga aimed at businessmen well into their 40s. In Japanese, the word Seinen means "young man" or "young men" and is not suggestive of sexual matters. (The female equivalent to seinen manga is josei manga.)

It has a wide variety of art styles and more variation in subject matter, ranging from the avant-garde to the pornographic. Because of the emphasis on storyline and character development instead of action, some seinen series are often confused with shōjo, or girls' manga.^{[citation needed]} This is especially true of seinen comedy series such as Chobits, and Chi's Sweet Home, or seinen drama such as Twin Spica. Other examples of seinen manga include: Gantz, Battle Royale, Vagabond (manga), 20th Century Boys, Monster, Blame!, Ghost in the Shell, Akira, Berserk, Battle Angel Alita, Drifters and Elfen Lied. Rumiko Takahashi's Maison Ikkoku is sometimes classified as seinen, although this is disputed by some fans.