Kyouko is a tall and slim girl who is known to be cute and pretty by most of her classmates with chest-length chestnut-brown hair that is usually tied up (whenever she is outside of school or in a casual setting) with bangs swept to the right side and golden-brown eyes.
Kyouko is most often seen donning her normal school uniform, which consists of a short-sleeved white shirt (long-sleeved in the winter), a red bow around her neck, a dark pleated skirt, black knee socks, and shoes. She occasionally wears her uniform vest, sweater, or blazer.
At home, Kyouko dresses in relatively casual and simple attire such as plain t-shirts and leggings or jeans. She keeps her hair tied up and at times, styled with hairpins. When cooking, she wears an apron.
Kyouko is normally a very energetic and popular person who always creates a happy atmosphere around herself. She is a hard-worker in all aspects of her life, and, according to Izumi Miyamura, she scores above 90% for all her tests. When nervous or embarrassed, she tends to switch to a violent state. This is seen when Kyousuke Hori asks if Miyamura was her boyfriend, resulting in her turning red and shoving a hot ladle into his face.
When she does ear cleaning, nail clipping, or massaging, she does it aggressively, which makes her feared by her family, her friends, and Miyamura. Miyamura has also mentioned in the chapter―that a q-tip looks like a weapon with a considerable offense when Hori wields it.
Hori is somewhat of a sadist masochist- however this is only when it comes to Miyamura. Whenever he suddenly flips his personality to that of an abusive boyfriend for a short while (at her request), Hori enjoys the treatment and feels refreshed afterward. This is probably due to the fact that Miyamura is always calm and non-abusive.
She is also shown to be very jealous at times girls are flirting with Miyamura to the point where Yuki Yoshikawa and Tooru Ishikawa call her "Ice Queen". In some parts of the manga, she is also referred to as "Hannya" or the "Goddess of Jealousy". Over the course of the story, she does not seem to be too bothered with girls talking to Miyamura anymore but instead, worries that he might love a man. She once told him that it's okay to love another woman but not a man.
- The name Kyouko means "capital city" (京) (kyou) and "child" (子) (ko).
- Kyouko's surname Hori means "moat" (堀).
- Her married name Miyamura means "temple, shrine, palace" (宮) (miya) and "town, village" (村) (mura).
- Hori seems to have inherited a few things from her parents:
- Hori stands at around 163cm, equal to about 5'4", and weighs 48kg (in Chapter 21: SOS, note that the weighing scale says 41kg), which is the same as Izumi Miyamura.
- Hori does not wear any makeup when she's at home.
- Hori is terrible at tongue twisters compared to Miyamura, even though her grades are always better.
- Hori likes to eat mikan (a type of citrus fruit).
- Hori dislikes stew.
- Hori's favorite anime is Riho's World.
- Unlike Miyamura, Hori absolutely loves horror movies.
- In Chapter 43, Hori is both a sadist (a person who derives pleasure, especially sexual gratification, from inflicting pain or humiliation on others) and a masochist (a person who derives gratification, sexual or otherwise, from their own pain or humiliation) as she appears to enjoy being shouted/hit at by Miyamura.
- It also happened in Chapter 46 and Chapter 54, as well as episodes 8 and 9 of the 2021 anime.
- Hori won second place in the Horimiya character popularity contest on November 17th.
- Hori is the oldest character in the cast, albeit, not counting parents and teachers
- Hori often took baths with Kakeru Sengoku in the past, but it is hinted that they stopped doing that only by the time they reach teenage hood