Suzushiro Mizuki is a first year high school student who's considered very attractive by many of the guys at school, and is constantly getting asked out. Unfortunately for Mizuki, he is also a guy. Even his crush, Fujiwara, thinks of him as a girl friend. Only his best bud Ichimonji Takeru seems to know and care that he's a man.
The story begins with Mizuki receiving yet another confession of love by a guy who won't back down even after Mizuki tells him he's male near a supposed Magic Mirror that grants the wish of anyone who confesses to someone before it. Meanwhile, the Norse god of trickery Loki has decided to turn her eye to the mortal world for a new form of entertainment. Seeing Mizuki's situation, she decides to have some fun and turn Mizuki into an actual girl.
Waking up with two new breasts and one missing willy, Mizuki reveals his situation to Takeru and desperately looks for a way to turn himself back into a boy and hide his new form. Just to add to the problem, Loki has decided to enroll in Mizuki's school to directly provoke and antagonize him.
The manga ran from 2014 to 2016, and is complete with 11 volumes.
Boku Girl contains examples of:
- All Just a Dream: Chapter 95.5 is a very, very NSFW one. In it, Mizuki and Takeru finally end up having sex while Mizuki's still a girl. This is Mizuki's dream, by the way.
- Can't Get Away with Nuthin': When Takeru finally admits his romantic interest in Mizuki, his mother promptly forbids him from seeing Mizuki any further, because she does not approve of a homosexual attraction to another boy. And when Mizuki counters by revealing his Gender Bender, Mizuki's father promptly forbids him from seeing Takeru as well, as it would not be chaste for a maiden of the Suzushiro family to carry on with a boy either.
- Childhood Friend Romance: Mizuki and Takeru have been best friends since they were kids. After the Gender Bender thing, Takeru begins to feel strongly attracted to Mizuki, but tries to suppress it as much as possible. Mizuki doesn't notice it at first, but later begins to feel attracted to Takeru too. Things turn out for the better though, as they both begin dating at the end of the manga.
- Cleaning Up Romantic Loose Ends: Mizuki resolves his love triangle by remembering he only loved Fujiwara's femininity, and ended up growing to see her as a good friend. Upon this revelation, he rejects her confession to pursue his true love.
- Contrived Coincidence: In this case, they're contrived by Loki, usually. For instance, the one time Mizuki is forced to wear womens' panties is also the one time he ends up flashing them to Fujiwara, courtesy a toy with Loki's appearance hooking onto and pulling up the skirt he'd been made to wear at the time.
- Did Not Get the Girl: In the final arc, Fujiwara confesses that she's fallen for Mizuki and doesn't care what his biological sex is. However, he turns her down, decides to live life as a girl, and hooks up with Takeru instead.
- Disguised in Drag: Now that he's a girl, Mizuki's boys' uniform counts as a crossdressing disguise.
- Ecchi: The manga doesn't shy away from showing Mizuki's new assets.
- Entertainingly Wrong: Characters who learn Mizuki is female, but not that he was transformed into a girl, usually take Mizuki's declarations that he's a guy as something along the lines of Mizuki being transgender. Another character, Fujiwara, who does know Mizuki was male but sees him doing girly things (such as wearing panties) goes in the opposite direction and assumes Mizuki wants to be a girl. Their ideas are somewhat validated by the fact that Mizuki decides he wants to live as a woman at the end of the series.
- Erotic Dream: Chapter 95.5 has Mizuki dream of getting his first time taken by Takeru, in almost softcore hentai detail.
- Erotic Eating: Because of one of Loki's pranks, Mizuki sees a shrimp in a really... interesting form. He still forces himself to eat for Fujiwara and the way he does it is beyond suggestive. The shrimp even gets censored!
- Forceful Kiss: In Chapter 17, Takeru just can't hold his confused self back anymore and kisses Mizuki in a heated moment. Mizuki doesn't take it well.
- Gender Bender: Caused by Loki the trickster god.
- Heir to the Dojo: Mizuki is the heir to the the Suzushiro Aikido Dojo, which is why he is either Weak, but Skilled or a pint-sized powerhouse. Takeru is one of Mizuki's father's students.
- If It's You, It's OK:
- As Mizuki starts to become more feminine, he begins fantasizing about Takeru. Then even when Mizuki is temporarily turned male again, he's still attracted to Takeru. In the final chapter he decides to remain a girl and they hook up.
- Late in the series, Fujiwara confesses that she has fallen in love with Mizuki and doesn't care whether Mizuki is biologically male or female. Unfortunately for her, Mizuki decides to hook up with Takeru instead.
- Jizzed in My Pants: As a result of a badly placed rope (courtesy of Loki). Not familiar with the sensations, Mizuki thought it was a case of Potty Failure.
- Jumping the Gender Barrier: Mizuki and Takeru have been best buddies since childhood and Mizuki appreciated that Takeru was the only one who treated him as a guy. After Mizuki turns into a girl, Takeru suddenly finds himself strongly attracted to Mizuki, while Mizuki eventually also begins to think of Takeru as more than a friend. Things get really difficult for Takeru after Loki feeds him a dream of a truly female Mizuki. Immediately afterward, Takeru notes that he can't view Mizuki as a guy any longer.
- Locked in a Room: Chapters 39-41 feature Takeru & Mizuki getting locked in the gym storage room immediately after Loki gives Takeru a dream featuring himself in bed with a truly female Mizuki and Mizuki reveals he has a minor issue with claustrophobia and needs some comfort.
- Mistaken for Gay: Invoked by Yamada in chapter 42. In a desperate bid to dissuade his would-be fiance Tamako he publicly proclaims his love for Mizuki. Mizuki's assertions that he's male do nothing to dissuade him.
- The Modest Orgasm: In chapter 11, following a prank by Loki that left Mizuki straddling a rope. It was so modest not even Mizuki fully realized what had happened, thinking instead it was a case of Potty Failure.
- Panty Shot: The one time Mizuki is forced to wear womens' underwear (because his boxers were left out to dry during a rainstorm) is also the one time he ends up flashing his undies to Fujiwara.
- Secret Keeper: Takeru and Mei are the only ones who know Mizuki was transformed into a girl. Yamada knows Mizuki is physically female, but not that he was gender bent. As far as Mizuki knows, the same is true of Loki. As of chapter 38, Fujiwara has also been let in on the full secret.
- Shout-Out: In chapter 6, there is a "Lordgenome" clothing store.
- Supporting Harem: Almost everyone, both male and female, is head-over-heels for Mizuki. It's obvious Mizuki and Takeru will be the Official Couple from the beginning, though.
- They Do: Mizuki decides to live as a girl, and finally confesses to Takeru. They're dating by the last chapter.
- Third Law of Gender Bending: Initially averted; Mizuki's rare forays into female attire have been voluntary and temporary, and only three people know his secret. As more characters become aware and eventually Mizuki is outed as physically female, he finds himself in feminine clothing, up to and including the girl's uniform, more often.
- Tomboy: Fujiwara is a closet tomboy, having loved mechas since she was a child and often behaving more masculine than the manliness-obsessed Mizuki.
- Triang Relations: Mizuki has a crush on a girl named Fujiwara, who is more interested in Takeru. Meanwhile, Takeru is developing an awkward attraction to Mizuki's new female body.
- Troll: Loki's reason for being and the entire reason she does anything. She likes to cause a mess then sit back and enjoy the show.
- Unresolved Sexual Tension: Mizuki and Takeru, mostly from the latter, though in later chapters Mizuki appears to be reciprocating, though that may be due to Loki's interference.