If you're looking for manga similar to Upotte!!, you might like these titles.
Takuma Zushi just wanted to be left alone. He sleeps in class and skips club. While going home, he sees a girl walking into the woods and decides to follow her. There he witnesses a fight between two sword masters with the prize being the ownership of the "Kandachime", a sword that can take human form. That girl, Otowa Hagane was about to lose when he naively steps into the fight...
2 votes
Each of these mangas tells the tale of a group of deadly weapons which take the form of human girls/women.
If you want more girl-weapon transformations you could try reading Kandachime. It has has swords take form of human girls (rather than guns like it was in Upotte!!) and it's probably better than Upotte!! in terms of story, characters and art.
Ishikawa Takuya, a high-school student who doesn't stand out in any particular way, is surprised when his principal asks him to take care of some transfer students. He is even more surprised to find that there are actually 30 charming female transfer students in his care, who have come from a boarding school that was destroyed in a fire! At first it seems like a dream come true, but then he notices their knives... and guns... What kind of school did these girls come from?
1 vote
Both of these series are about a group of cute schoolgirls who are surprisingly vicious and deadly warriors.
It's been seventeen long years since the Fleet of Fog―a mysterious, unmanned fleet of powerful vessels that appeared out of nowhere―took control of the oceans, barring humanity from traveling between continents or islands. During those years, people the world over have dreamed of a revolt that would let them take back the seas, but there's been no hope―until now. A weapon powerful enough to damage the Fog's vessels has finally been invented, and there's just one way of getting the critical information and prototypes from Japan to America, where the weapon can produced! The submarine I-401, with its humanoid avatar―a "mental model" named Iona, who's taken the shape of a young girl―was once part of the Fleet of Fog, but has chosen to side with humanity. Now captained by Chihaya Gunzo and his crew, the I-401 is the only ship under human control that can move freely through the seas. But she answers only to her captain, and he answers to no one.
1 vote
If you liked the concept of weapons taking form of girls, you might want to give Aoki Hagane no Arpeggio a try. It features battleships personified as girls and woman.
Miho Nishizumi, a new transfer student to Ooarai All-Girls High School, would like nothing more than to enjoy a peaceful, stress-free school life. Unfortunately, her new school just revived its tankery program and enlists Miho to put together a team so that they may compete in a national tournament. As Miho struggles to overcome her turbulent past with tanks, she must first learn to tread lightly with her eccentric companions. Can Miho possibly plow through the challenges and master the art of tankery, or will she get left behind in the dust?
1 vote
Looks like it's the season for making manga targeted at military otakus (or trying to turn those people into lolicons). Like Upotte!!, Girls & Panzer revolves around moe schoolgirls handling military equipment, except instead of girls with guns we get girls with tanks. The tank trivia is also there (just like gun trivia could be found in Upotte!!). At least Girls & Panzer doesn't have fanservice...
1 vote
Both manga revolve around schoolgirls with guns. Riot Girls has adventage over Upotte!! in that it's just a oneshot, so the nonsens ends after a single chapter. Nonetheless if you liked one, you might like the other one too (keep in mind Upotte!! has some instances of questionable ecchi).
This is a slightly peculiar world where the shipgirls live in. A lively and enjoyable school life for girls from different factions will begin at the naval port of Azur Lane. Living out their lives to the fullest, these girls get into various shenanigans—slowly but surely!
The story of a young man's journey to realise his life-long dream of becoming an air force pilot.
Isami Kondou is a young man who has just started his university life studying at the National Defense Academy - an organization with the aim of training students to become high-ranking officials of the Japanese Self-Defense Force. During his overly-strict life at the JSDF academy, he experiences grueling times, and also happy and joyful times, all the while growing into adulthood. This is the youthful story of a young man conquering all obstacles that come his way!