Masaya Aoyama is the central character, Ichigo Momomiya's, classmate and romantic interest. He later reveals that he shares her feelings and they begin dating. Masaya knows Mew Ichigo's real identity, but initially pretends otherwise as he knows Ichigo does not want him to know. Ichigo describes Masaya as "smart", "cute", "very athletic" and "popular at school". He is also depicted as being a polite and calm person, though he does have moments when he yells at others in anger and acts jealous and possessive regarding Ichigo. Towards the end of the series, Masaya reveals that as an orphan, he began acting like a "perfect child" to be adopted, in reality, however, he felt sick of humans and disgusted by how they treat the planet. He also reveals that Ichigo is the sole exception, and it was only with her that he felt like a "real human being". As the series progresses, it is revealed that Masaya is the Blue Knight, but that Masaya did not know that he was the Blue Knight, nor did the Blue Knight appear to have any knowledge that he was Masaya. Once Masaya becomes aware of his transformation, he realizes it was born from his desire to protect Ichigo. Shortly after this revelation, Masaya collapses and reawakens as Deep Blue, the leader of the aliens and the Mew Mew's final enemy. Deep Blue claims that he created Masaya in order to deceive the world until the time was right for his awakening. Masaya sacrifices himself by releasing the final Mew Aqua inside his body in order to stop Deep Blue, and is revived when Ichigo gives her life to save him. In turn, the mew aqua remaining his body then saves her. At the end of the series, Masaya decides to go to England to study the endangered species used for the Mew Project and the Mew Mews hold a mock wedding for Masaya and Ichigo before he leaves. In Tokyo Mew Mew a la Mode, Masaya is the first to sense the new danger to the Mew Mews, and encourages Ichigo to return to help her friends. Towards the end of a la Mode, he also returns to Tokyo.
The Blue Knight suddenly appears at the end of the fourth volume of the manga as an unknown alien male to rescue Ichigo during a battle with Kish. He tells Ichigo that he "is hers" and that he was "born to protect her". After his first appearance, the Blue Knight reappears whenever Ichigo is in danger to protect her, and disappears after the situation is resolved. As the series progresses, Ichigo attempts to learn his true identity and suspects both Ryô and Keiichirô, before learning near the end of the series that the Blue Knight is an alternate persona of her boyfriend, Masaya. It is revealed that this persona was created out of his desire to protect Ichigo. After his true identity is revealed, the Blue Knight, now knowing he is Masaya, fights with Mew Ichigo and the Mew Mews, and it revealed that Masaya and the Blue Knight are both alternate personalities of their worst enemy: Deep Blue. The Blue Knight disappears after Masaya transforms into Deep Blue. In Tokyo Mew Mew a la Mode, Masaya notes that he does not possess the powers he had as the Blue Knight. In the anime adaptation, the Blue Knight is given a larger role, fighting with the Mew Mews several times, advising them to the weaknesses of the monsters, and encouraging them.
Ryô Shirogane is a wealthy high school student, the head of the Mew Project, and the owner of Cafe Mew Mew. Ryô is said to be a genius in the manga and the anime say that his IQ exceeds 180. After his parents' death when he was ten, he moved to Japan to continue his father's work with his father's assistant Keiichirô. After he finished developing the technique for injecting genes into the future Mew Mews, he first tested it on himself to ensure that the subjects would not be harmed. As he was not a compatible host, it only gave him the ability to change into a cat at will for up to ten minutes at a time. Ryô also built Mew Ichigo's, and later Mew Berry's, respective robot assistants, R2000 and R3000. Ryô tends to talk to the girls in an abrupt manner, but displays a strong sense of personal responsibility, particularly with regards to the Mew Mews. He helps Ichigo several times, in his cat form, "Alto", including by kissing her to help her change back human. He seems to fancy Ichigo though it is not shown he does.
Keiichirô Akasaka is the manager and baker at Cafe Mew Mew and Ryô's partner in the Mew Project. Keiichirô worked with Dr. Shirogane, Ryô Shirogane's father, on the Mew project five years before Tokyo Mew Mew is set and continued working on it with Ryô after Dr. Shirogane's death. Keiichirô's age is given neither in the manga nor the anime adaptations. The Mew Mews consider him to be a gentleman, with a charming, tactful, and kind personality. He can be mischievous and flirtatious as well; for example, he has offered to kiss Ichigo to change her out of her cat form.
Tasuku Meguro is Berry Shirayuki's best friend and love interest in Tokyo Mew Mew a la Mode. He has lived beside Berry since they were born and has been best friends all their lives. After her mother's death, he began giving her a hug each morning to replace her mother, and to express his own feelings. He also roller blades a long distance to her new school to check on her. When he discovers Berry has become a Mew Mew, he reassures her that it does not bother him and he will never quit being her friend. As the story progresses, initially he tries to hide his feelings, but finally admits to himself that he is in love with Berry. Eventually he asks her if he can stop being her "childhood friend" before kissing her, apologizing, and running away before she can answer. While he berates himself for his behavior, Duke uses the opportunity to hypnotize him and turn him against Berry. He is freed from the spell when Berry confesses her own feelings and kisses him, after which he asks her to stay with him forever and she agrees. After the Saint Rose Crusaders are defeated, Berry and Tasuku celebrating being in love and continue working at Cafe Mew Mew as the cafe's new door-to-door delivery service.
Masha is a robot created to detect chimera animals and Mew Aqua. Originally called by her model number of R2000, Ichigo renames her "Masha" after Masaya. After the aliens are defeated, Masha chooses to stay with Ichigo when she goes to London with Masaya. In addition to detecting the chimera animals, Masha eats the jelly-fish like parasites that come out of the victims after they are defeated. She can also merge with Mew Aqua found by the Mew Mews to transform into the Mew Aqua Rod, allowing any of the Mew Mews to perform the Ribbon Aqua Drops healing attack. Primarily communicating by repeating the sounds "pi" and "tweet", Masha does not appear to be designed to support high-level speech initially, though in Tokyo Mew Mew a la Mode she is once shown speaking in a complete sentence. In the Tokyo Mew Mew anime adaptation, Masha is male instead of female, has a more extensive vocabulary, and tries, unsuccessfully, to assist the Mew Mews in some battles.
Ucha (ウチャ Ucha?) is the second robot created by Ryô. Appearing only in Tokyo Mew Mew a la Mode, the R3000 is given to Berry Shirayuki who names him Ucha. Ucha has similar abilities to Masha, but speaks in complete sentences and complains a lot. It also has a different appearance, resembling a strawberry with bunny ears, and can transform into Berry's staff weapon.