Matt is often annoyed by Mimi's antics, but accepts her as a member of the team. Matt gets frustrated easily by Mimi's lack of common sense such as when she withholds the fact she has a (albeit broken) compass and cooking fuel.
Four years later, they seem somewhat closer, as Matt mentions at one point in the English Dub that he's been talking to Mimi over the phone from America. In the original version they do not interact.
Mimi sees Sora as a close friend and the two bond, often over being the only two girls in the group to begin with. They enjoyed pampering themselves in the shower in "The Crest of Sincerity."
Mimi finds it hard to deal with Izzy's tedious method of analyzing things and eventually turns out to be right in her own accord. She eventually turns out polite towards him.
In the manga of Digimon Adventure Mimi and Izzy are trapped in some ancient ruins and Mimi runs off crying about how Izzy likes his computer more than her. Also in the manga, while asleep, Izzy dreams about Mimi: "Sure Mimi, I'll hold your hand."
According to the Digimon Adventure novels, she was Izzy's classmate prior to the series; when Mimi's friends were making fun of Izzy for carrying around a laptop during summer camp, Mimi did not join in simply because she "didn't find any reason to".
According to the Digimon Adventure novels, Joe was Mimi's summer camp counselor. She notes that his face is stiff and decides he is not a very reliable leader (something later disproved harshly to her).
Mimi treats Joe as if he is still her camp counselor and has a large dependency on him for much of her problems; she expects him to do his job like he should.
Later in the series, as Mimi seriously questions her duty as a DigiDestined and leaves the group, Joe decides to stay with her and protect her, something she hadn't expected from him. She also learns that while Joe is no longer her counselor, he has always felt a duty to take care of her even when she thought he was an annoyance, despite him proving to her later in the series that he was and is a capable leader.
Also in Digimon The Movie, Joe left a Heart-shape gift at Mimi's house.
Mimi and T.K. are close in the first part of Digimon, most likely to be minors from the group, before the appearance of Kari. They often are seen talking, sharing things, playing and laughing together. Four years later, it can be seen that they are still good friends.
Mimi invites Willis and Davis over for summer vacation
Yolei looks up to Mimi from the first time they meet. Mimi is fond of Yolei and treats her well.
Mimi is the first of the previous DigiDestined to extend trust to Ken; when Palmon is attacked by an artificial Digimon created by Arukenimon, Mimi does not hesitate to ask Ken for help.