Yui Hirasawa
Yuiazu After watching the Light Music Club's performance during the freshman reception, Azusa thought of Yui as a very talented guitarist and this thought eventually led her to join the club. Shortly after joining however, she regrets thinking highly of Yui and rather thinks of her as a student who just likes to procrastinate, and goof around. Azusa does however acknowledge Yui's good sides, like her ability to successfully accomplish things when determined, her ability of perfect pitch, and her great heart and affection towards her friends.

Despite being better at guitar than Yui, she insisted that Yui played the lead guitar due to her seniority (though in some songs, usually opening songs, Azusa plays the lead guitar instead). Before Azusa's first concert, Yui was sick and probably could not recover in time. Azusa was the one who brought up the idea to cancel the concert, since it would not be good for anything if the whole band would not be present in her eyes. When Yui actually showed up, Mio told her to apoligise to Azusa since she was the one who worried the most about her.

Yui had quickly become attached to Azusa, who usually struggles with Yui's attitude of petting or spoiling her and constantly nags about it, although Azusa's resistance has diminished over time. An example of this is her nickname, "Azu-nyan" ("-nyan" is a Japanese suffix associated with cats), given to her by Yui after she wore fake cat ears. First, she called the name "weird", but over time, she accustomed herself to it and even used it as the basis for her own given name for Jun's cat ("Azu-nyan 2") and to finally blow Ui's cover when Ui stood in for Yui by asking her about her nickname, which Ui did not know. When Yui crosses the line though, (by trying to kiss her for example), Azusa will not hold back using violence to stop her, like slapping her face before the school concert or elbowing her in the stomach (when she mistakenly thought Yui was about to kiss her instead of her guitar).

Azusa's strict and diligent personality often conflicts with Yui's laid-back character, but nonetheless Azusa is generally willing to help Yui, as seen when Azusa created a study plan for Yui or helped Yui out at a talent show to help impress Yui's neighbor. On other occasions however, she is very strict and does not allow Yui to goof around as she pleases. Overall, despite trying to hide it with harshness, Azusa is fond of Yui and the two have become very close, even rooming together during the band's trip to London.

Mio Akiyama
Mio and Azusa

Mio and Azusa have much in common, being the "sane" members of their band. Despite having so many things in common with Mio (to the point where they seem like sisters), they have not interacted personally very often, and mostly relate to each other when they agree in decisions, especially having the urge to practice when the others don't. In the band, she looks up to Mio mostly because of her maturity.

When the two had the chance to be alone together after school on day, Azusa tried to start practicing immediately since she knew Mio was the only one that would listen to her. Azusa even tried to give Mio chocolate on Valentine's Day. However, she sometimes unintentionally makes remarks concerning Mio's weaknesses, such as her weight.

Ritsu Tainaka
Ritsu and Azusa

Other than Yui, Ritsu is can be considered her next closest senpai (probably because of Ritsu's friendly nature towards her as well).

In the anime, Azusa had laughed over Ritsu's embarrassing moments twice, once during Mio's special training when Ritsu wore a maid's dress; the other time was when Azusa found out that Ritsu was going to play Juliet in the class play.

Ritsu often pulls Azusa into a chokehold, either because of Azusa laughing at her, or Azusa indirectly insulting the band or Ritsu herself. When Ritsu overheard Azusa badmouthing about about Ritsu being a "lazy and irresponsible leader", Ritsu promptly put her in a chokehold, although the latter only did not really seem to mind that comment. After that comment, the two of them continued to grow closer. Azusa has praised Ritsu's cooking at one time, yet in the same episode, Azusa was the one who pointed out Ritsu's father's underwear in the living room. Ritsu bullied Azusa in the manga more often than in the anime.

Despite being disappointed with the club president's immaturity, Azusa still held her respect and admiration for Ritsu and the band's coherent performances. When Azusa first mentioned that she was joining the Light Music Club, Ritsu had practically pounced over her. Ritsu and Yui had been scolded by Azusa numerous times when they were lazing around and procrastinating during their training sessions and training camps.

Ritsu has always seen Azusa as a valuable member of the band. When Azusa was considering quitting the Light Music Club, Ritsu also initiated a performance for Azusa which successfully kept Azusa in the club. Near the end of the series, Ritsu could be seen worried over Azusa becoming the next president of the Light Music Club. Ritsu would act responsibly as the leader whenever the club did something for their junior, most memorable scenes were when Ritsu went all out trying to recruit freshmen for Azusa so that she would not be lonely after they graduate. 

Tsumugi Kotobuki
Azusa and Tsumugi Azusa finds Tsumugi very beautiful, and envies her hair and large eyes, and later started teaching her how to play the guitar when the two were alone in the club room. In the manga, Azusa teaches Mugi to play guitar for a time period longer than is adapted in the anime. She also finds Mugi's snacks to be delicious and has enjoyed eating her snacks.

She is shocked to find out that Mugi's house had a housekeeper and was impressed with the villa that Mugi served to the girls during the training camp.

Ui Hirasawa
Azusa and Ui 2 Azusa and Ui had been good friends since their first year of High school. At that time, Ui introduced Azusa to the light music club, accompanying her to the light music club's freshman reception performance and persuading her to join the club.

After that short event, they became good friends. After the other members graduate, Azusa was worrying about new club member of the new light music club. Ui and Jun helped her by joining the club and together trying to gain other new members.

Jun Suzuki
Azusa and jun Azusa was probably introduced to Jun by Ui. After that, they had become good friends, despite Azusa often disapproving of Jun's laid-back personality. In times when Jun needs Azusa help, Azusa is willing to help her, such as when she took care of Jun's cat while Jun was away even though she had no idea what was involved in taking care of a cat. Azusa and Ui also tried to persuade Jun so that she would want to join the new Light Music Club. Looking at the condition of the Light Music Club and knowing that at least 4 members were needed, Jun quit her previous club and willingly joined the Wakaba Girls music club as the bassist.
Sawako Yamanaka
Azusa with bunny ears When they first met, Azusa thought of Sawako being a "pretty" person. Sawako's laid-back and immature attitude, however, quickly forced Azusa to change her mind. Azusa tends to nag when Sawako shows her undependable nature, but she is surprised when the latter actually shows authority or is dependable. Despite Sawako being a teacher, the two have a friendly connection. Azusa is, like Mio, often the target of Sawako's dress up-rampages, a fact she greatly dislikes. When the original HTT members graduated and Azusa became the new club president, she often quarrels with Sawako but also asks for her help sometimes.