Peke (ペケ, Peke?) Voiced by: Satomi Arai

Lala's all costume robot, who acts as a module to form her clothing. Peke is exceptionally devoted to Lala and has the ability to shapeshift into any kind of clothing for her to wear, but this also drains her power supply. As her batteries run out, the clothing Lala wears will slowly dissolve, until it completely disappears. To recharge, Peke simply needs to sleep. Using a dress-form program, Peke has the ability to take on a human form, with the appearance of a young girl.

Haruna Sairenji (西連寺 春菜, Sairenji Haruna?) Voiced by: Sayuri Yahagi

One of Rito's classmates and the girl of his affections, Haruna has similar feelings for him, having been attracted to his kind, gentle nature since junior high. Despite her growing love for Rito, which she believes to be unrequited, she usually suppresses her feelings and cannot confess to him because of her friendship with Lala, who also loves Rito. However, with some encouragement, she tells Lala of her ordeal, to which Lala accepts, claiming Haruna as her rival for Rito's heart, while remaining friends. She lives with her older sister in an apartment and has a severe fear of ghosts and the supernatural, the exception being Shizu Murasame, to an extent. When frightened, she has a habit of grabbing the nearest thing around her – typically Rito – and swinging wildly, in an attempt to get rid of whatever frightens her. There is also a running gag to where Rito is about to confess to her, only for something (or someone) to come between it.

A highly responsible person, Haruna's personality can sway her classmates' hearts to vote for her as their class representative, even when she did not run to be a candidate. She is affiliated with the tennis club and a southpaw. According to Mio, Haruna's measurements are B78, W55, H80.

Lala Satalin Deviluke (ララ・サタリン・デビルーク, Rara Satarin Debirūku?) Voiced by: Haruka Tomatsu

The female protagonist of To Love-Ru, Lala is the princess of Deviluke, whose family rules the Galaxy. As such, her hand in marriage is sought from across the Galaxy as she is (presumably) the successor to the Galaxy's throne. A rather childish girl, she is somewhat näive regarding the culture and customs on Earth. Lala initially runs away from home, as she does not wish to get married to any of her suitors, and due to an accident, ends up naked in Rito's bathtub. Upon arriving on Earth, Lala pretends to love Rito to keep herself from getting married, but really does fall in love with him after she misinterprets a statement that Rito shouts in self-defense.Although Lala appears to be somewhat airheaded, she is well known on Deviluke for her genius-level intellect and enjoys making all manners of inventions, often prompting some disastrous effect or another. Throughout the series, she frequently tries to get Rito to love her, although her grand gestures generally end up putting Rito and company in embarrassing situations. Although Rito frequently chastises her for causing embarrassing and otherwise troublesome incidents, Lala rarely shows any form of negativity towards him and even states it is impossible for her to hate him. Even after finding out that he was in love with Haruna as well, she instead cheered and stated that they could both marry him, and becoming even happier after he accidentally said "I love you" to the rest of the female cast, as they could all be together.

Eccentric, playful and intelligent, Lala isn't shy, to a point where it feels almost natural for her to be in the nude (the only exception of this occurs when Lala catches a personality changing fever from another planet, making her very shy). Like all citizens from Deviluke, Lala's physical abilities vastly exceeds that of a human (in one instance, she manages to blow away a typhoon just by shouting) and has a distinctive tail with a shape of a spade on the end that can shoot a destructive beam. Oddly, her tail is very sensitive, causing her friends to nickname it her "weakness" (all female Devilukeans' tails are more sensitive than a male's) despite being able to throw Run and Saki to a wall while they mess with it. Unfortunately, Lala is bad at cooking. The food she cooks is either inedible or extremely spicy. While the fact that Lala is an alien is initially a secret, it becomes common knowledge relatively soon after her arrival with no one making a big deal about it. According to Ringo, Lala's measurements are B89, W57, H87.

Rito Yuuki (結城 リト, Yūki Rito?) Voiced by: Akeno Watanabe

The male protagonist of To Love-Ru, Rito is a 16 (currently 17) year-old high-school student. Rito used to be on the soccer team in junior high and was quite good, but quit because he was constantly helping his father with his mangaka duties, thus did not want to leave his sister Mikan alone in the house. Mikan comments he is very good at the most "useless little things", like crane and festival games (e.g. hoops, catching fish, squirt guns). Along with the numerous useless little things Rito is good at, he is also an accomplished florist, gardener, and horticulturalist.

Rito's nature is borderline clumsy, where he always ends up ogling or groping the many girls in the series (though mostly unintentionally). It is only by accident that he encounters Lala Satalin Deviluke, and despite his enduring feelings for Haruna Sairenji, Rito shows signs of developing deeper affection towards Lala throughout the story but is unsure if what he feels is actually love. This is shown again when he couldn't help but think about Lala even though he was with a naked Haruna. It is recently revealed that he is in love with Lala, but he is also in love with Haruna. At the end of the series, he confesses to Lala, but tells her he also loves Haruna, yet she is happy on both parts. He is confused as polygamy is illegal in Japan where Lala replied that once he is king of the universe the laws of earth no longer apply and forces him to go tell Haruna (strapping a jet pack to his back). Right before he was about to tell her, she moves out of the way, just like when he confessed to her very early in the series, leading him to state "I love you" to all of the female cast with the exception of Momo, Mikan, Golden Darkness, and Haruna herself. The ending implies that his "love" troubles will continue on into the future.