MomoJirou

MomoJirou is the femslash ship between Momo Yaoyozoru and Kyouka Jirou from the My Hero Academia fandom.

Canon
Kyouka and Momo are very close friends with each other. During the Unforeseen Simulation Joint Arc, the two fought villains together with Kaminari, proving to work well as a team. During the End of Term Test Arc, Momo helped Kyouka to study for the class midterms.

When the class split up to go shopping for the training camp, Momo and Kyouka paired up and went off shopping together. Kyouka also has proven to be somewhat defensive of Momo, as she hit Hanta for upsetting the latter with his distasteful comment about her Quirk. The same can be said the other way around; when Kaminari and Kouda were pressuring Kyouka that she should use her musical talents in the Cultural Festival, Momo jumped in to say that it was her decision.

Momo, Kyouka, Shouji, and Tsuyu end up being separated from the rest of the class during the Provisional License Exam arc. They went into a building and Momo and Kyouka are seen next to each other quite a bit. Afterword, Kyouka is shown to be supporting Momo up along with Tsuyu and stay together in the lobby and second half of the exam. They both also placed their targets in the same spots as each other. When the results are handed out, Momo shares her score with Kyouka and blushes as she tells her how amazing it is.

During the Cultural Festival arc, Momo says that she can help the band by playing the keyboard and Kyouka says it'll be a big help. Consequentially, they are both on the band team and are paired up together once again. When thinking up names for their band, Jirou rejects suggestions from all three of their other teammates in favor of immediately agreeing to Momo's idea and saying it was cute.

While having a break from practicing for their concert, Momo complements Kyouka by saying she seems "to be born to teach," Kyouka blushes saying it's nothing and quickly changes the topic to the tea Momo is making which in turn makes her blush and start to gush about it with her eyes shining.

After their concert, Momo and Kyouka go off on their own and are shown to be having a good time and laughing at a drink in the shape of their teacher, Cementoss. While Momo's interest in girls is limited to arguable interactions with Kyouka and Kendou, Kyouka is shown to be attracted to other girls fairly blatantly. In the first BNHA movie "Two Heroes", when Melissa appears in her formal wear, Kaminari, Mineta and Kyouka are all shown to be floored by her beauty and blushing.

Just before this, both Momo and Kyouka go to where their group is meeting up together and late. Later in the movie, Momo had used up all that her quirk would allow and falls, only to have Kyouka catch her and make sure she is okay.

Moments

 * Momo and Kyouka interact and are seen next to each other a number of times throughout the series, usually in the background of panels.
 * Kyouka has been caught on a few occasions staring at Momo's breasts, and this can be taken as she is jealous of her or crushing on her, though it is most likely the latter as she is usually blushing in these scenes.
 * On multiple occasions, Kyouka has been shown to protect Momo, particularly when her quirk causes her to become slightly nude.
 * During the attack on the USJ, Momo created a thick sheet of insulation that destroyed nearly all of her top, leaving her breasts fully exposed. Kyouka became incredibly flustered and rushed to cover her naked friend, hugging her tightly while Momo laughed.
 * In the Season 3 outro, Momo and Kyouka can be seen standing next to each other in a frame of the whole class.
 * Momo and Kyouka share a moment of just them in the Season 3 outro, with both of them linking arms, back to back, and then Momo lifting Kyouka onto her back, both smiling. Their shoulders form a heart.
 * In the Season 3 outro still, a few class 1-A members can be seen walking along a beach. Kyouka can be seen ahead of Momo, outstretching her hand and looking at her, while Momo runs over to her.
 * When Mina is showing off her dorm room, there is a bulletin board filled with pictures of her friends. One of them contains just Momo and Kyouka standing next to each other.
 * While preparing for the concert, Momo is nervous and Kyouka comforted her.
 * In the first light novel, Kyouka complements Momo saying that she is a good teacher. Momo then blushes and is pleased. A few pages later, it is revealed that Kyouka wants their friendship to blossom further and is worried as to how Momo's family may see her.
 * The first light novel also had a small portion where Kyouka brought headphones, that she does not need, to share with Momo and listen to music on a bus ride. Momo also mentioned Kyouka and blushes when the girls of their class and Class 1-B were having a slumber party and talking about crushes.
 * In the 4th volume of the light novels, Momo had prepared an entirely different thermos filled with a tea different from what the others were having for Kyouka to help with her voice.
 * The 4th volume of the light novels also featured a page for the two where Momo complained to Kyouka that she wished she could have watched her from the front row. However, she claimed that she was still content with watching her sing from behind. This causes Kyouka to blush and nudge Momo with her shoulder and Momo then leans in.
 * The second BNHA Movie, "Hero's Rising" has Kyouka being worried for Momo because of how much she was using her quirk. The two were also paired together as a team along with Ashido.

Fanon
In canon, the two are shown to be opposites which are often shown off to a greater extent in fanon as the two fit most ship dynamics. They are usually portrayed as soft lovebirds that are also powerful and in general mesh well together.

Although both girls have potential male love interests, the great emphasis on sincere friendship between the girls quickly made their ship popular. In this context, Kyouka's admiration for Momo's femininity and charm is treated not only as evidence of her complex because of her tomboy-ish appearance, but also as an indication of her sapphic identity.

However, it's worth noting that as of recent chapters, more evidence has been brought in for Jirou's potential male love interest: Denki Kaminari, who has been heavily implied to view Kyouka as the most important person in his life. As such, while KamiJirou is often brought up in ship wars with MomoJirou already, it is now to an even greater extent.

Momo, for her side, does not demonstrate the same level of affection, but MomoJirou supporters tend to justify this with her alleged status of Kyouka's crush and thereby the interpretation of their relationship as a character's search for reciprocity on the side of their love interest. Given one of Momo's other ships, TodoMomo, and her open to interpretation affection for Todoroki, such uncertainty makes Momo a key character in ship wars between the supporters of the two ships.

MomoJirou is the most popular BNHA femslash ship in Archive of Our Own, the 7th most tagged pairing under the My Hero Academia fandom, although most of the fics have them in the background instead of the main focus.

Fandom
FAN FICTION
 * Jirou/Momo tag on FanFiction.net
 * Jirou/Momo tag on FanFiction.net

TUMBLR

Trivia

 * The support of the ship in western fandom is so wide that when Horikoshi tweeted a sketch with the walking Momo and Kyouka, this tweet received huge feedback from people who took it as the author’s nod to the ship or direct support from his side. Some of the replies include an edited screenshot of Bakugou holding a sign reading "gay rights", a reaction meme implying that the person was shocked by how blatantly homoerotic the drawing was, and a more simple one reading, "Hm, beautiful couple".
 * Momo and Kyouka's friendship has been described by Horikoshi, MHA's creator, as "particularly intimate" in the Ultra Analysis book.