Manga that explore Gender Identity

It's about the relationship between a bigender person and an agender person. It deals with these people learning about their own gender identities and other people not understanding it. It's a long-ish oneshot, albeit still too short to deal perfectly with the theme, and it has its flaws (it's a little biphobic imo), but an interesting read nonetheless, specially for being the first oneshot I've ever seen with canon non-binary charas. Beware of some bi/transphobic language.

A girl meets a childhood friend and finds out she's now a girl, having transiotioned during the time they hadn't met. Here on mangago you can only see the 4koma picture, but you can find the rest of the chapter on Dynasty-Scans: https://dynasty-scans.com/chapters/childhood_friend_yuri

This story is, unfortunately, REALLY short. It's about two girls who reunite 13 years after high school, and one of them is transgender. She tells the other girl she was only able to accept herself as a woman because of her. It's cute and Makoto is really cute as well, that's why I enjoyed it despite it being so short.

I adore AS. It has multiple characters who are transgender (Aracne), genderless (Belial), or don't see their genders as part of their identity (Alexiel, Rosiel), and also characters who learn to accept their gender through the story (Kurai), between other cases that would be more spoiler-ish. It's, however, a very heavy story that involves sibling incest as its main pairing, grotesque imagery, complicated familial relationships, reincarnation, angels and demons, etc. Beware.

I wasn't sure about adding this manga to this list. Since the author was previously a hentai mangaka this manga has some nsfw scenes, and some tropes that kinda bother me, like a gay character who's a Yandere, and a lesbian character who blackmails the protagonist. However, I liked how this manga has characters of multiple sexualities, and the main character is a crossdresser who doesn't seem very sure about his gender, and really enjoys looking cute and girlish. TW: rape attempt, homophobia.

This manga is about Sara, a trans girl who finally started living as a girl now that she's in high school. We follow Sara as she goes to school, makes new friends, falls in love, etc. It's a very light-hearted story

The main character is a cis girl named Hina. Hina's first crush, Itsuki, comes back to the city after over 10 years... but Itsuki is now a woman, and to top that, she's straight. How things will go from now on? TW: constant misgendering.

This manga tells the author's autobiographical story about how it was for her to undergo sex reassignment surgery. It talks a lot about the procedure and how the author feels before it, during the recovery, and afterwards. It's short and it's completely translated now!

This manga was written by a trans author. It tells the story about Ryou, a trans boy in high school who wants to start a clothing brand. We follow him as he starts his brand with his new friends and at the same time deals with his gender issues.

tw: misgendering, transphobia

The story is about Yukari, a high school girl who gets involved with a group of college students who work with fashion, and George, a bisexual man who Yukari falls in love with, and who is one of the college students. This manga doesn't really explore gender, but it does have a transgender character in the main cast, a woman named Isabella. It's overall a very good mature manga.