In "Ladybug & Cat Noir", Alya first meets and befriends Marinette when she defends her against Chloé's bullying. Since then, Alya and Marinette have been best friends, often hanging out with each other or helping each other out. While amused by Marinette's ditziness and inability to act normally around Adrien, Alya encourages her to talk and do things with/for him, such as giving him a birthday present or inviting him to a movie. Alya is also very forgiving and accepting of Marinette's flaws, such as when Marinette accidentally deletes Alya's video of Ladybug (which led to the theft of Alya's phone for several hours), and she immediately tells Marinette that it was no big deal, though she is disappointed Marinette had not told her sooner. Despite considering Marinette a ditz sometimes and being perplexed by her constant disappearances, Alya loyally stands by her, and she appreciates Marinette's kindness. In "Befana", Alya is even willing to stand up against Befana and rally her friends to defend Marinette. She does whatever she can to comfort Marinette when she is sad about Adrien's inability to hang out with them in "Glaciator" and "Captain Hardrock".
In "Catalyst", unlike Marinette, Alya believes in Lila's stories and lies believing that Marinette was jealous of Lila trying to go on a date with Adrien.
This continues in "Chameleon", when Marinette tries to tell her and Nino about Lila's deceitful nature, she refuses to believe her without proof. Yet being a true friend, she returns to normal seat at the end of the episode, refusing to leave Marinette alone. She even continues to help Marinette admit her feeling for Adrien in "Backwarder" and " The Puppeteer 2", by leaving her alone with him while at the wax museum.
She even helps Marinette babysit her sisters and Chris in "Timetagger". Like her friends, Alya knew that her best friend wasn't a cheater or a thief seen in "Ladybug" when she vouched to defend her. But became shocked that Marinette was expelled from school and that belief in her made Alya resist being akumatized as well as try to prove her innocence. Advised Marinette not to jump to conclusions as she did before and needed proof, unknown to her that Marinette was right about Lila setting her up.
At one point she promised Marinette that she'd give up looking for the answers to Ladybug's identity to protect her in "Feast". In an alternate future in "Cat Blanc", she was extremely happy for Marinette, when her best friend finally admitted her feelings to Adrien finally becoming a couple and praised her for the effort. Became shockingly surprised that Marinette attempted to admit her feelings to Adrien in "Felix".
Meanwhile, Alya is a huge fan of Ladybug, running a fan blog about her called the Ladyblog. She is always trying to learn more about her idol, including her secret identity however she would respect her desire to keep it secret. In "The Pharaoh", she reveals that she has figured out that Ladybug must destroy an important object of a supervillain in order to defeat them, which impresses Ladybug. She also seems aware that she and Cat Noir's transformations are only temporary. Her search for Ladybug's identity is relentless, once mistaking Chloé, a cosplayer, for being Ladybug. On multiple occasions, she has stepped in to help Ladybug, such as when she turns on a hose for her per request in "Ladybug & Cat Noir". In "Gigantitan", Alya rallies her friends in an effort to help Ladybug defeat the villain. Alya is also willing to help her and Cat Noir with less important tasks, such as when she agrees to act as supervillain "Cardboard Girl", to help them help Mr. Damocles live out his superhero dream in "The Dark Owl." According to her in her Instagram page she aware that there is nothing going between Ladybug and Cat Noir except a strong partnership.
Her wildest dream, to work alongside Ladybug, comes true in "Sapotis", when Ladybug asks for her help and temporarily trusts her with the Fox Miraculous. While working with her as Rena Rouge, Alya becomes so excited that she needs Ladybug to keep her on track about the task at hand. She questions Ladybug's complicated solutions for stopping villains but remains loyal to her. The two work well together as a team, but when the mission is complete, Alya is hesitant to return the Miraculous, telling Ladybug that they and Cat Noir would make a great team. However, not wishing to betray Ladybug's trust, she returns the Miraculous and keeps her time as Rena Rouge a secret from others.
Alya continues her adventures as Rena Rouge in "Syren", where she helps Ladybug and Cat Noir round up some escaped panthers, and looks forward to her next adventure after she returns the Fox Miraculous. As Rena Rouge, she also takes part in helping the heroes defeat Hawk Moth's army in "Heroes' Day". Continues her adventures as Rena Rouge in "Miraculer".
In "Feast", she continues to help Ladybug by trying to unmask Hawk Moth. She continues to be on good terms with Ladybug as they came together for group photo with their friends.
As Lady Wifi, her frustration with her search becomes intense, as she complains that heroes should not hide their identities.
Although Alya and Adrien rarely interact, they appear to be friends. Alya easily asks him for favors and can joke on his behalf. She sees him as a kind person and knows that he would not hurt anyone deliberately. However, her interactions with him are limited to when she tries to set him up with Marinette. In "The Evillustrator", she was paired with Adrien and Nino for a science project. In "A Christmas Special", when she heard that Adrien had gone missing Alya showed concern for him as a friend when she and her classmates went looking for him. In "Befena", she was talking to Adrien about coming to Marinette's birthday party. In "Captain Hardrock", Alya had gotten used to Adrien's inability to hang out with them but remained hopeful of other opportunities.
In "Chameleon", she finds Adrien's behavior towards her and Nino rude and strange unknown that it was Lila disguised as Adrien. Alya also accepted Adrien's invitation to come to the Wax Museum in "The Puppeteer 2", using the chance to get him and Marinette alone. She is also paired up with him for art project and believing they'll bond together through their passion for photography.
Alya was shocked to see Adrien coming aboard the houseboat with Kagami surprised that his father let him out in "Desperada". When Kagami told Marinette that she would have to choose in the love department one day, Alya knew that Luka and Adrien hadn't made their choice yet either. However, unknown to her that he is in love Ladybug which is her best friend's alterego. In "Felix", Alya agreed with Marinette in sending Adrien a video care package to make him feel better about missing his mother. However, upon being tricked by Adrien's cousin Felix with him leaving a nasty message she began to doubt her friendship with him leading her to seek revenge as her akumatized form. After being deakumatized she received a video message from Adrien explaining what happened happy to know they are still friends. During an alternate future in "Cat Blanc", she supported Adrien's relationship with Marinette.
Though not as interested in Cat Noir as in Ladybug, Alya is a fan of him, finding him cute. She is also searching for his alter ego, at one point contemplating it being Adrien unknown to her that she was right. In "The Pharaoh", when Cat Noir asks Alya if she wants to know how old he is, she says that she will be able to tell that herself as he is about to detransform, and she laughs in amusement when he runs away from her. During "The Dark Owl", she didn't mind when Cat Noir and Ladybug approached her for a favor in accomplishing Mr. Damocles' dream. She aware that there is nothing going between Cat Noir and Ladybug except a strong partnership and he gets along pretty well with Carapace unaware that the two are best friends under the masks. 
Alya meets Cat Noir as her alter ego Rena Rouge in "Sapotis", and she has fun jovially teasing him. She also appreciates Cat Noir's trust in her and willingness to help her, and they bond as good friends as they help Ladybug execute her plans. The two continue to work well together in "Syren", "Mayura" and once again in "Miraculer".
As Lady Wifi, when she sees Cat Noir coming to save Ladybug, she mockingly comments on how romantic the situation is and calls Ladybug his "lovebug."Horrificator", but it leads to issues when Alya finds out Nino added a kissing scene into her script without telling her.
In "Animan", she hears Nino tell Marinette that he has a crush on Alya (although Nino only says that because he doesn't have the courage to confess to Marinette). Alya is disgusted because she thinks of him as a brother. However, after they spend an afternoon together locked in a zoo cage, an event that Alya doesn't want to give Marinette all of the details about, Alya seems to have changed her mind about him, although she is still able to get frustrated with him on occasion. Beyond that event, Alya and Nino have remained together, dancing together in "Despair Bear" and going to André's ice cream cart as a couple in "Glaciator". They'll often hug each other when scared, shown in episodes "Reflekta" and "Captain Hardrock".
They hold each other during "Zombizou", and Nino stays with Alya even after she is infected by the titular villain. In "Anansi", Alya enjoyed playing with Nino and heard that he would do anything to protect her as she saw him come for her while being Anansi's prisoner. And yet, saw him hold off his own against her but hoped Ladybug would return soon.
Then, Alya saw Ladybug return with a new ally in complete awe and then suspicion of how the hero spoke similar to her friend. After her sister, Anansi had been saved Alya was amazed that a new hero entered the scene and asked for his name-calling himself Carapace. Once Nino came back, Alya admits she saw what he did for her. In "Heroes' Day - Part 1", she unveils that she is Rena Rouge to Nino and that she was aware he was Carapace. When meeting with the other heroes they argue about covering each other.
In "Chameleon", Alya comforts Nino who has his feelings hurt by Lila who disguised as Adrien and she told him that he looks good even without his cap. They both practice moving in synchronization to perfect their battle skills in "Miraculer". She is aware that he gets along pretty well with Cat Noir unaware that the two are best friends under the masks. In "The Puppeteer 2", she was comforted by Nino when she felt a little uncomfortable looking at a statue of her akumatized form.
In "Stormy Weather 2", they talked about how much their lives have changed because of Ladybug. The two continue having a loving relationship with each other going on dates seen in "Timetagger", "The Puppeteer 2", seen in a few of her Instagram photos and having a dinner date with him and her family in "Battle of the Miraculous".
Like Marinette, Alya detests Chloé. She finds her very snobby and rude, but she recognizes that Marinette is more likely to suffer because of Chloé than she is herself, feeling sorry for Marinette when she and Chloé are partnered up for a school project. During her searches for Ladybug's identity, Alya spots Chloé with a Ladybug-themed towel, and a Ladybug yo-yo, misleading her to think Chloé is Ladybug. After Chloé discovers that Alya took a picture of her locker and gets her temporarily suspended, Alya, enraged by Ladybug having such a horrible alter ego, goes to unmask her after transforming into Lady Wifi. She continues to believe she's found Ladybug's true identity until the real Ladybug and Cat Noir arrive to save a cosplaying Chloé from Lady Wifi's clutches.
In "Zombizou", she calls Chloé even worse than Hawk Moth because of her cruel nature, and when Alya finds out that Chloé is the cause and focus of the villain's rampage she suggests giving her to the zombies. In "Malediktator", Alya like everyone else takes pleasure in Chloé leaving for New York. Therefore, she’s quite irked and jealous of the fact that Chloé is being welcomed back with a huge party. She is aware of her actions as Queen Bee knowing she didn't prove her might as a hero the first time. However, she is fine working with her as Rena Rouge in "Mayura (Heroes' Day - Part 2)", despite not calling her by her hero name.
Alya is friends with Rose and Juleka. When Rose is feeling upset about her notebook in "The Notebook", Alya agrees with Juleka that it is awesome and writes that Rose is the "sweetest person she knows" into it. In "Reflekta", Alya showed support for Juleka when she went to the park with her friends to shoot another class photo.
She also enjoys hanging out with them on several occasions. Seen in "Syren", where they went to the movies and in "Frightningale", as extras in Clara's video.
Alya bonds very easily with Manon because of her experience with younger sisters. As she says in "Prime Queen", Manon is one of her favorite girls to hang out with, next to Marinette. In "Stormy Weather", she pretends to be a unicorn princess, exciting Manon, and during their entrapment within a shield of ice by Stormy Weather, Alya tries to entertain her in order to distract her from their dilemma. Alya is responsible and caring to Manon, relieved after Ladybug and Cat Noir save her to find Manon safe and still sleeping in Marinette's room. She even has fun while playing with Manon in Wax Museum.
While it's not known if Alya knows that the Pharaoh is Jalil, she figures out that his necklace is his important item that Ladybug needs to destroy. Captured by the Pharaoh, Alya is both frustrated by her kidnapping and thrilled to be a part of the action while waiting for Ladybug and Cat Noir to show up. She takes the time to ask him questions about his plan, but as soon as she discovers that she is his sacrifice, she is terrified and uses her recording to call out to Ladybug for help. Amusingly, though, when Ladybug is tricking the Pharaoh to sacrifice her instead of Alya, Alya takes it as an offense, annoyed that the Pharaoh doesn't think she is a good enough sacrifice.
Alya loves her younger sisters dearly and enjoys playing with them. She knows how to handle them pretty well, as complemented by Marinette, but her patience can run out with them over time, and she is very stern with them when they disobey her too often. When Alya discovers that they have been akumatized, she does everything in her power as Rena Rouge to bring them back to normal.
In another Instagram page Alya loves to make a pillow fort with her younger sisters and she also mentions that if they want to become good reports they would need a lot practice with a camera.
At first, Alya is a bit startled by Trixx, but she gets extremely excited once he introduces herself and she deduces that he helps her transform. She wants to keep him and the Miraculous after defeating the Sapotis but listens to his point about being trustworthy and respectfully returns both him and his Miraculous to Ladybug.
In "Syren", despite having to return Trixx and his Miraculous at the end of a mission, Alya is happy to have him as her kwami and excitedly waits to see him again for their next adventure which is seen in Catalyst (Heroes' Day - Part 1) and again in "Miraculer" and "Startrain".
Alya is aware that Gabriel is Adrien's father but she is unaware that he's Hawk Moth.
She knows that he is responsible for the akumatized villains in Paris. She works along with Ladybug and Cat Noir to defeat him.
During "Feast", instead of looking for Ladybug's identity she'll try to help Ladybug unmask Hawk Moth. Unknown to her in the "Battle of Miraculous", through akumatizing Chloe as Miracle Queen, Hawk Moth discovered she was Rena Rouge.
As a sister, Alya appreciates Nora trying to protect her but understands that she doesn't always need her protection. But when Alya sees her akumatized into Anansi, she became worried for her, and once she is returned to normal, Alya embraces her as the two spend time together at the ice rink. In an instagram photo the two in even take a picture together.
When Lila transfers to Collège Françoise Dupont, Alya is quickly fascinated by her stories. Alya posts Lila's "story" about how Ladybug saved her life and then they became close friends on the Ladyblog.
Alya hadn't seen Lila until "Catalyst (Heroes' Day - Part 1)" when the class got to talk to her via webcam. Alya noticed Marinette's anger towards Lila and told Marinette just because Lila flirted with Adrien, unaware that she is a liar.
In "Chameleon", she doesn't understand why Marinette has a grudge for Lila, so Marinette tells her and Nino that Lila "lies with every breath" and says that Lila has never met Ladybug in her life. When Alya asks her to prove her lies, Marinette in an attempt to show them that Lila's wrist isn't hurt, she throws a rock paper tissue towards Lila, but Lila catches it with ease, proving Marinette's claim. But Lila covers it up with another lie saying during her travels she witnessed a traumatizing sight in India seeing a man who had their eye gauged out.
In "Oni-Chan", Alya disapproves of Marinette's stalkish behavior towards Lila simply chatting with Adrien. But at the end of the episode she is surprised how Marinette stopped, followed by her saying Adrien would never love a girl like Lila.
Alya even trusted Lila to watch over her younger sisters while she and Nino went off to the movies in "Timetagger".
In "Ladybug", Alya quickly takes Marinette's side when she is framed for cheating on a test by Lila. She advises Marinette not to jump to say Lila is the culprit, then no one would believe her, and they needed proof. Unknown to her that Marinette was right about Lila setting her up.
Despite meeting Luka in "Captain Hardrock", she doesn't know him too well, but upon seeing Marinette look at him romantically she refereed to him as her "new compass".
In "Desperada", she agrees with her friends that Marinette is more comfortable with Luka than with Adrien seeing him with "new boyfriend potential". She is aware of Viperion as a new ally but doesn't know it's Luka and at some point she tried to take a photo of him but upon seeing that it didn't turn out too well and she hoped to get a second chance to see him someday.