HUMANS

Isshin Kurosaki

Ichigo and his father have a very unusual relationship. It is very clear that they love each other like most fathers and sons do, but Isshin tends to "train" Ichigo by physically assaulting him, usually when he's asleep, prompting a frustrated Ichigo to retaliate rather violently. Even so, Isshin deeply cares about Ichigo, to the point were he saved his body (Kon was in his body at the time) from an attack by the Grand Fisher, and discussed his parenting skills with Uryū Ishida's father. Ichigo often addresses Isshin as "temee", which is a very offensive form of "you" in Japanese, something no ordinary son would do to a father (especially in Japan, a country where elders and parents are highly respected).
Orihime Inoue

Originally a friend of Tatsuki, one of Ichigo's friends from school, she admired Ichigo from afar until he pacified the soul of her brother early in the series. They have become quite close since then and Ichigo has shown to be able to talk to Orihime about things that trouble him as revealed when he was unable to stop the Shinigami from apprehending Rukia and spoke to Orihime about it in order to get it off his chest. Due to exposure to Ichigo she developed spirit powers manifesting itself as six spirits. She lives alone since her brother passed away sometime before the series started. She loves him, but it is not known whether he shares similar feelings. He did go into a state of depression when she was attacked by Yammy and he couldn't protect her. It should also be noted that he became immediately hostile towards Ulquiorra after he said that he kidnapped her. He also managed to stop one of Grimmjow's attacks barehanded after Orihime pleaded to him to not die. Having been kidnapped by Ulquiorra, Ichigo and the others went to Las Noches to save her, just like he'd traveled to the Seireitei during Rukia's capture. In his current battle with Ulquiorra, Ulquiorra speculates that one possible reason why Ichigo might have withstood his cero without the use of his mask is because of her. Orihime has also demonstrated that she is perceptive, mostly when it comes to Ichigo. She has the uncanny ability to detect Ichigo by scent and sense his spiritual pressure, even when masked by a powerful barrier.
Chad

Chad is one of the best friends of Ichigo from the school. They once fought together against a group of bullies, and after that, promised to protect and help each other in any situation that calls for it. Ichigo mispronounced his name wrong as Chad instead of Sado when they met, but he continued to call him Chad afterwards.
Uryū Ishida

One of the last remaining Quincy left in the world. He initially had an intense hatred for the Soul Society, especially Captain Mayuri Kurotsuchi, due to the fact that they were responsible not only for his grandfather's death, but for the decline of his entire species, and directed his anger towards Ichigo despite being entirely innocent on that matter. Ichigo, likewise, viewed him with contempt and disdain for endangering his friends lives by "calling forth" an army of hollows to his school. However, after his defeat, Uryū and Ichigo now consider themselves friends despite Uryū's usually cold demeanor and Ichigo's short-tempered persona.
Tatsuki Arisawa

Tatsuki is a student at the Karakura High School, one of Ichigo's classmates, and is his childhood friend and karate partner. When they were children, Tatsuki regularly saved Ichigo when he was getting beaten up, as well as cheering him up when he was upset. During most of their interactions, Tatsuki and Ichigo share an equal amount of trust, respect, and loyalty to one another, and will often give each other a fair amount of emotional support when needed. Tatsuki also cares deeply about Ichigo's well-being, as most of his friends do, and was quite sympathetic towards him when his mother died. She even stated that she "hated seeing him suffer as much as he did when his mom died". Recently, Tatsuki is now wel-aware not only of the existence of the arrancar, but of the fact that Ichigo is a shinigami, and witnessed his fight with Grimmjow during his assault on Karakura town. Obviously concerned for her childhood friend, but in no position to help, Tatsuki decides not to tell the others about this, especially Ichigo until she deemded it necessary. When Orihime gets taken away to Hueco Mundo, Tatsuki is noticeably upset at her sudden disappearance and frantically searches for her. When she finds nothing, she immediately confronts Ichigo, aware of his role as a shinigami, to ascertain the truth. However, Ichigo, knowing that she wouldn't provide much assistance in the rescue attempt (and would die in the process), stubbornly refuses to inform her of anything, in which Tatsuki becomes angry and violent over his reluctance to explain himself. She then reveals to him that she is able to sense both his and Orihime's reiatsu, and can see Ichigo in his shinigami form, as well as the arrancar. After coldly denying his 'involvement' in Orihime's sudden disappearance, even after she revealed her knowledge about his dual-life, Tatsuki punches Ichigo's head through a window and shouts at him for not telling her what he knows. She is restrained by Keigo and Mizuiro, while Ichigo walks away coldly telling his friends not to get involved. However, while unnecessarily cruel, severing his ties with his friends was the only thing he could have done to ensure their survival. Unwilling to give up on both of her friends, she is later accompanied by Keigo Asano and Mizuiro Kojima to Urahara's Shop and sees Ichigo leaving for Hueco Mundo.
Masaki Kurosaki

Masaki was, as Ichigo described in the English dub, "the heart of the entire family", and was Ichigo's main female influence during his childhood. As Tatsuki Arisawa stated to Orihime, whenever he saw his mother, regardless of what his current condition is, even if he was crying, his usual happy, smiling persona would immediately return, as if nothing ever happened to him. Masaki's death at the hands of the Grand Fisher completely changed Ichigo's personality; he turned from a happy, smiling mama's boy to a scowling, short-tempered individual who distanced himself not only from his friends and classmates, but from his family as well. He also vowed not to let anyone he cared about to die because he couldn't protect them, and shut away most of his emotions in order for him not to feel that emotionally-scarred ever again. Recently, however, he seems to have slightly opened up to his friends, though not as much when Masaki was still alive.