As we know, there are many different kinds of "love", and people often confuse "friendship love" or "brotherly/sisterly love" with "romantic love". In this trope two people love each other. Some or many people, perhaps even those who know the two well, take this to mean they are romantically involved, but contrary to popular belief, they are just friends.
The key to this trope is that though affection and even love exists between the two people, it is not romantic (though in some cases there was the potential for it at some time in the past). Neither of the two friends have (or probably ever will have) any interest in the relationship becoming romantic, unlike in the Just Friends trope which requires this. However, one or more bystanders/others think that the love is a romantic one and may try to call them out on it.
The two may be (but are not necessarily) Heterosexual Life-Partners, Platonic Life-Partners or Like Brother and Sister. If a third person gets involved with one of the people and then finds out about the other it can turn into an Imaginary Love Triangle.
If they are the same gender, this trope can overlap with Mistaken for Gay. Different to She Is Not My Girlfriend in that the two are not remotely romantically interested in each other, it is all in the eyes of the beholders. For cases when the two turn out to be related, see Relative Error.
Contrast Everyone Can See It where instead of mistakenly identifying the type of affection between two people, the bystanders are simply being more perceptive than them; and Strictly Professional Relationship where one or both would like to be romantically involved but their professionalism prevents it.
Not to be confused with Just Friends where, despite saying they are strictly platonic, the friends are really not.
Sometimes Truth in Television.
NOTE: This is a love trope so there may be unhidden spoilers ahead.
- In Beauty Pop Narumi saw Kiri hanging out together with Ochiai, and when the latter closed in on her to get rid of a bug from her hair, Narumi thought they were kissing and assumed they were in a relationship.
- In Bloom Into You, during the training camp for the student council's School Play, Riko Hakozaki, a teacher and the student council's assistant advisor, invites Tomoyuki Ichigaya, her friend and fellow member of her theater group, to coach the actors. Some of the students notice that they get along, and ask if they're in a relationship. Riko, who is in a relationship with Miyako, the manager of the coffee shop, truthfully insists that Ichigaya is just a friend, while Ichigaya mentions that he has a girlfriend.
- A sub-plot in Chapter 925 of Detective Conan has Idol Singer Yoko Okino and soccer star Ryusuke Higo making a scandal when reporters saw them shopping together in what looks like a date. They were actually just school mates looking to buy a gift for their former teacher who is retiring.
- In Kannazuki no Miko, Chikane and Souma are the two most popular students at their school and everyone, including the main character Himeko, thinks they are the perfect match for each other and must definitely be dating. In reality, there is nothing going on between them and both are interested in Himeko, and Himeko ends up with Chikane.
- When New Transfer Student Chizuru from Kimi to Boku sees Yuki and Shun talking, he mistakes them for boyfriend and girlfriend. When Shun's friends tell him that he isn't a girl (nor is he Yuki's boyfriend) Chizuru scoffs and believes they're insulting "her" chest size. When Chizuru sees Shun in the male school uniform he faints.
- Noel and Sasa from Mint na Bokura are considered the Official Couple of the class since they hang out all the time. Nobody except Noel's sister knows that Noel is a boy.
- Mobile Suit Gundam 00 features a rather hilarious scene in its second season when Mileina asks Setsuna and Marina if they are a couple. Both reply negative in complete deadpan (and in perfect sync) without a hint of embarrassment or sexual tension. If anything, they seem to love each other as something between Platonic Life-Partners and surrogate mother and son, since Marina is a dead-ringer of Setsuna's Missing Mom.
- It's a running gag in Venus Versus Virus for Sumire's friends to mistake her and Lucia for a couple.
- Takatsuki and Saori from Wandering Son are mistaken for being boyfriend and girlfriend by their respective Stalkers with Crushes. This assumption goes away when they learn Takatsuki's sex.
- In Zetsuai 1989, the Idol Singer Kouji Nanjo is seen talking to a very cute Girl Next Door named Serika Izumi in public, and it reaches the news. Kouji is actually interested in Serika's older brother Takuto, a promising soccer player, who is furious at Kouji because this puts his innocent little sister in the spotlight and he fears that the Izumi's horrible Dark and Troubled Past will also be featured in the spotlight. Which is exactly what happened.
- In Angel and Faith, after Giles' will made generous provision for Faith, his great-aunts come to stay. As Faith shows Sophronia to the master bedroom...
Sophronia: How awkward. I just realised this must be where you and Rupert used to... well.
Faith: What? I wasn't sleeping with him.
Sophronia: No, of course not. Middle-aged men leave everything they own to young ladies out of fatherly affection.
- In Elseworld's Finest: Supergirl & Batgirl:
- The media think Supergirl and Lex Luthor are together. However Kara regarded him as a friend and surrogate father before finding out that he considered her to be a useful pawn.
- Rumor also has it that Bruce Wayne and Barbara Gordon -alias Batgirl- are together, but they're just friends although Bruce actually encourages those rumors.
- At least one comic has had civilians mistake Supergirl for Superman's girlfriend. They're cousins.
- Ultimate Galactus Trilogy: Sue asks Lawson to see him without clothes. Stark is confused, he's in the room, and she wants him to get naked? Reed clarified: he's an alien, and she's interested in his biology.
- In Co-op Mode, Armsmaster thinks Beetle Knight and Lady Bug are dating, when in truth it is all in his head. The same goes for Coil, but does not take it as far as Colin, who even concludes - wrongly - that Beetle Knight is only an overzealous fanboy, which is not helped by James' lack of a Corona Pollentia.
- In Fall Back 1940, Leo thinks Tom and Hermione are a couple. They aren't.
- Prodigal Son: It is revealed that Astrid stole something from Hiccup's room, Fishlegs steps in and bails her out by convincing the tribe that she was secretly in a relationship with Hiccup before he disappeared.
- In To Hell and Back (Arrowverse), Eddie mistakenly believes Barry and Kara to be a couple when he meets the latter before the Queen Thanksgiving Dinner. When he voices this out loud, Oliver and Kal burst out laughing while Barry and Kara act like they're going to throw up.
- In the Kim Possible fanfic The Touch Of Green Fire, a jealous Kim mistakes Shego and Drakken for a couple. They're not. Shego isn't even interested in men, and Drakken is too into his job to care about romance.
- Cassandra explains to Mahanon that pretty much everyone in Haven thinks he and Victoria are romantically involved, in Twice Upon An Age: All This Sh*t is Twice as Weird. As the two are really Like Brother and Sister, he's quick to correct her.
- In Megamind, Roxanne admits to "Bernard" that despite popular opinion, she and Metro Man were never involved. They were very close friends, but he "wasn't her type".
- Most of the school in Me and Earl and the Dying Girl assumes Greg and Rachel are dating once they start hanging out more. However, it's a The Not-Love Interest plot.
- In The Return Of Sherlock Holmes 2016, the antiques dealer Hudson mistakes Holmes and Watson (who is female in this adaptation) for a newlywed couple he was expecting. Holmes and Watson take advantage of his error and play along, allowing them to question him without divulging their true identities.
- Star Wars: In Return of the Jedi Han Solo thinks that the love between Luke Skywalker and Princess Leia Organa is romantic. However, although Leia did kiss Luke (though only to piss off Han), they can't be in love because they just found out they were siblings.
- In The Wedding Singer, Robbie and Julia are mistaken as a couple by Faye, who senses a closeness between them, though they are planning a wedding for Julia, so it can be understood why the confusion exists. Julia replies that they are brother and sister and they both pull quick childhood pranks on each other in a good-natured way.
- This happens to Harry and Hermione a few times throughout the Harry Potter books.
- In The Deathly Hallows Ron sees Harry and Hermionie's affection, mistakes it for romantic and gets jealous. Later Harry reassures him:
Harry: I love her like a sister and I reckon she feels the same way about me. It's always been like that.
- Invoked/Exploited in The Goblet of Fire by Rita Skeeter who publishes a rather nasty article that outright states (read: lies) that they had been in a relationship, causing everyone to believe they are, even Ron's mum.
- In The Deathly Hallows Ron sees Harry and Hermionie's affection, mistakes it for romantic and gets jealous. Later Harry reassures him:
- The Raven Cycle. In the second book, The Dream Thieves, local Bad Boy Kavinsky is convinced that Ronan's devotion to his friend, Gansey, must be romantic or sexual in nature. When Kavinsky accuses him of wanting Gansey, Ronan states that it's not like that and that Gansey is a brother to him, even more so than his real older brother. Kavinsky was right about Ronan having a crush on one of his male friends. He just guessed the wrong one.
- In Restoree the heroine, Sara, is kidnapped off the street and planted in the bed of the next heir to the High Lordship of Lothar to embarrass him. Instead they go with it and Sara poses as his girlfriend - to the considerable irritation of her Love Interest and the boy's real girlfriend Lady Fara.
- For much of Sense and Sensibility, everyone thinks that Elinor Dashwood and Colonel Brandon are in love. Elinor herself would think Brandon fancied her if she didn't know that he was in love with her sister, but their relationship is purely platonic—the main reason they gravitate towards each other at any social function is because they're usually the only two people in the room with some sense.
- Initially, in Survivors, Lucky is jealous of Alpha and Sweet's relationship. Alpha is The Leader of the Wild Dog Pack while Sweet is his second-in-command. Lucky thinks that they're mates until Sweet refers to Alpha as her "partner". She admits that it's normal for alphas and betas to be mates and so it'll likely occur with her and Alpha, but Sweet isn't currently his mate. She later ends up Lucky's mate.
- Village Tales: Happens in Ye Little Hills Like Lambs when a (perfectly nice) footballer in a pub assumes Canon Paddick and Sher Mirza are a same-sex couple and that the Canon's wee niece is theirs.
- In the Black Books episode "The Blackout" Fran sees her boyfriend having dinner with another woman (who turns out to be his sister) and showing affection for her. She mistakes his love for romantic and sees an Imaginary Love Triangle.
- Doctor Who:
- Series 4 has a Running Gag of the Tenth Doctor and Donna Noble being mistaken for a couple, which they are forced to repeatedly deny. Ironically, Donna was the first main companion of the new series not to be in love with the Doctor, as the two are Platonic Life-Partners instead.
- "Arachnids in the UK":
- Yaz's sister Sonya asks Ryan if he's Yaz's boyfriend. The two respond by stating that they're just friends. Sonya is pleased, as she seems to be interested in Ryan.
- Later in the same episode, Yaz's mum asks if Yaz and the Doctor are seeing each other. The Doctor has to ask Yaz if they are.
- Joan and Sherlock are frequently mistaken for a couple in Elementary. They're two 40-something-year-olds who live together and work together, but they're Platonic Life-Partners, and Word of God is there is no Ship Tease between them.
- In Everybody Loves Raymond, Ray and his mother Marie go on a cruise after Frank gets injured and can't go. Cue everyone on the cruise thinking they were a MayDecember Romance and Ray was just calling her his mother to avoid embarrassment. This was not helped by Marie pretending like her husband died so she could attend the meetings for the "Merry Widows" club.
- Sherlock. The title character and John are Heterosexual Life-Partners but their obvious (though prickly) affection for each other is frequently mistaken for being romantic.
- In Fire Emblem Awakening, this happens with Chrom and the Female Avatar in his Kid from the Future Lucina's supports with her, if they aren't married. When the Female Avatar denies having an affair with Chrom, Lucina gets extremely offended at the prospect of her not being attracted to her "amazing father" and practically demands she fall for him... before realising what she's saying. Time travel is weird.
- Played for laughs in Grand Theft Auto V where Tonya believes Franklin is Michael's lover just because the two of them had been hanging out for a while and became good friends. Franklin denies the claims, but Tonya thinks Franklin can do what he wants and that there's nothing wrong with him having sex with another man. Another scene plays out the trope in a more dramatic sense between Michael and Trevor where a Chinese gang hunts down Trevor, but grabs Michael instead and believe he is Trevor's boyfriend just because the two of them were seen hanging out around Trevor's trailer.
- Onmyōji: After Seimei agrees to let Yaobikuni, who has just delivered a Ship Tease-heavy dialogue about how he is her "fated one" who is the only one able to kill her, become his companion, Kohaku comments that Seimei is a "lady-killer", even though the two never develop a romantic relationship after that. They are now enemies by the way.
- In Pokémon Diamond and Pearl Mars from Team Galactic assumes that the player character and the professor's assistant are a couple on a date when they both approach her for a battle.
- Tales of Vesperia: Estelle is mistakenly assumed to have romantic feeling for Flynn, twice during the game.
- The first scene triggers as the group is leaving Halure. Estelle says it's urgent that she reach Aspio in time to deliver an important message to Flynn. Yuri then asks why and wonders if it's because she has a crush on him, which Estelle flatly denies.
- The second occurs during an optional skit, where it's Raven who asks Estelle the same question. She becomes irritated and reiterates that he and Yuri have the wrong idea. A separate skit has Karol wonder if it isn't the other way around, with Yuri and Flynn secretly harboring feelings for her, themselves. Yuri says no.
- Ace Attorney:
- Phoenix and Maya are constantly mistaken for a couple, mostly by Pearl, Maya's 9-year old cousin, who absolutely refuses to believe that they're not an item, going so far as to slap him whenever she thinks he's "cheating" on Maya.
- Pearl gets on the receiving end of this trope in Phoenix Wright Ace Attorney Dual Destinies, when Athena assumes that she's Marlon's girlfriend in DLC case.
- In Ace Attorney Investigations 2, Ray asks if Kay is Edgeworth's girlfriend after he gives up his badge to continue defending her from murder charges. Edgeworth responds that she is his assistant and that he is responsible for her.
- In Ikemen Sengoku, the main character being appointed as Nobunaga's chatelaine frequently causes other characters to assume that she's his lover too even on routes where she's interested in another guy instead. Unfortunately for her, this often leads to Nobunaga's enemies thinking that kidnapping her would be a great way to take advantage of the Devil King's one "weakness"...
- Steins;Gate has three main characters guess that Okabe Rintarou and Shiina Mayuri are dating, a suggestion Mayuri responds to with confusion, and Okabe responds to with a flat denial. Though things have potential to progress in that direction, at the respective times of the guesses, neither of them think of each other that way.
- In Agents of the Realm, when Norah and Adele leave in a hurry to fight a bleed, Kendell (not in on the secret at this point) thinks that the two are a couple on their way for some personal time.
- Disney High School:
- Kuzco and Jasmine are friends. Kuzco does not seem to have any real romantic interest in Jasmine, but flirts with her and calls her his girlfriend anyway, For the Lulz. Thus Jasmine keeps having to remind people they're not together, and Aladdin is even more convinced that he has no shot with her.
- At one point, Belle and Milo are happily chatting about books, leading to a Funny Background Event where Adam is marching over to kill him, except that his own platonic friend, Kida, is fighting to hold him back.
- In The Glass Scientists, Word of God is that other members of the Society think that Hyde and Jekyll are two people and lovers, an impression Hyde supports with glee.
- Im The Grim Reaper: When Chase's DND friends first meet Scarlet, they think she's his girlfriend since she was at his place before he was. He immediately denies it, but she decides to troll him more by informing them that she's slept over before. It helps add to their Ship Tease.
- In chapter 9 of Sleepless Domain, Outrageous Lime mistakes Heartful Punch's statement that she and Undine are "together" (as in, working together) to mean that they're a couple. Undine misses the implications, but HP immediately demands they change the subject. Lime agrees, saying she's "got a guy now, anyway".
- In Aaahh!!! Real Monsters episode "She Likes Me" Oblina and Krumm both think the other one is crushing on them, because some of their classmates say so. They both try to 'break up' each other and after asserting that they don't feel anything romantic, they end the episodes as friends, nothing more.
- Clarence. In "Pretty Great Day With A Girl", Belson and his friends think Clarence and Amy are hanging out because they're a couple, when really they're just hanging out as friends.
- In one Jem episode, Rio became jealous of a man Jem was working on a film with. Jem had no interest in them, but Rio thought she did.
- In the Justice League Unlimited episode "The Cat and the Canary" initially Green Arrow presumes Canary and Wildcat have a romantic relationship and is visibly disappointed. Canary explains him that she sees Wildcat as a mentor and second father, not a romantic interest.
- Miraculous Ladybug:
- In "Gorizilla", Marinette and Adrien hide in a fountain to avoid the latter's mob of Loony Fans. As soon as they get up, a man photographs them and puts the photo on the internet, leading to Adrien's fans assuming that Marinette is his girlfriend. Not that she minds too much.
- Their Alter Egos of Ladybug and Cat Noir also run into this in "Prime Queen", where Nadya Chamak tries to get them to admit they are dating to boost her show's ratings. In this case it's Adrien/Cat Noir that doesn't really mind the idea, since he has fallen head over heels for Ladybug.