So it's a character's birthday. He or she hoped that others will notice. They have known each other for quite a while, how could they forget?
Oh wait, they did forget. Even if the birthday person reminded them, it's all for naught. It may take a bit for the companions to get over the guilt, while the birthday person is guaranteed not to take it well.
Compare Forgotten Anniversary for the wedding day variant. If the birthday wasn't truly forgotten after all, and the other characters threw a Surprise Party, it's a Not-So-Forgotten Birthday. Can lead to a One-Person Birthday Party or Convenience Store Gift Shopping. The opposite of Not Their Birthday.
- In episode 7 in the first season of Beyblade, (in the dub version at least). Tyson is so excited about his match with Kai, he forgets about his own 13th birthday.
- IGPX: Occurs completely by the book in an early episode to Amy, who has had workaholic parents her entire life and only recently made friends with the members of the team. Her (absent) parents actually do forget her birthday.
- In one episode of Sailor Moon S it's Usagi's birthday and when she drops an unsubtle hint about what she wants for a gift, Mamoru reveals that he didn't know it was her birthday so he gets a huge slap in the face from her. Turns out she never actually told him when her birthday was. Even worse, she doesn't know his birthday either.
- One Kalos episode of Pokémon reveals that Jessie's teammates, James and Meowth, forgot her recent birthday. Only her Pumpkaboo remembered it. This is even more noticeable because the anime completely avoids characters aging.
- In episode 13 of My Love Story!! it's Suna's birthday but it turns out he forgot it himself. He didn't understand why his friends were acting so overly attentive towards him.
- On Yuki Yuna is a Hero, Karin had forgotten her own birthday, which she had never had a real celebration for before, and was thus surprised when the others show up to throw her a small party.
- An omake of Bleach reveals that Urahara's and Yoruichi's birthdays are forgotten every year and they have to celebrate them alone (although together). The reason for this is because their birthdays are December 31 and January 1.
- In one Donald Duck comic, Daisy Duck forgot her own birthday.
- In one Archie Comics story, Reggie Mantle's birthday is coming up. He overhears the gang wondering what to do for 'the most important man in town' and the egotistical Reggie assumes they're talking about him. Reggie nudges the gang into arranging a banquet at a fancy club...and it turns out that the gang was talking about an old war veteran who was born in Riverdale. And Reggie's the only one there who isn't in his golden years.
- Robin Series: Tim Drake's parents along with his girlfriend Stephanie and friend Ives are able to give him a surprise party for his sixteenth when his step-mother realized he had forgotten his own birthday. Earlier he had managed to forget Ive's sixteenth so Ives found it particularly funny.
- In Avengers Undercover, Nico completely forgets Molly's birthday because she's still struggling with PTSD.
- In one Harry Potter fanfic, everyone forgets Hermione's birthday because it happens to coincide with Talk Like A Pirate Day.
- Bon the Miffy, a My Little Pony: Friendship Is Magic erotic fanfic, centers around Lyra trying to make up for forgetting Bon-Bon's birthday.
- In How the Light Gets In a testament to what an awful mother Dinah Lance is to Laurel is her calling to wish Laurel a happy 29th birthday...the day after her thirtieth birthday.
- In ''Echo's of the past, people regularly forget Laurel's birthday. Its placement being near when super-villains get ready for an attack on the city didn't make help. Thea however always remembered, and was often the only one who did.
- In Sixteen Candles, the main character's birthday is forgotten by everyone due to the furor caused by her sister's impending (and last minute) wedding. Except for her younger brother. He deliberately ignored her birthday because he's a jerk.
- In Jaane Tu... Ya Jaane Na, Aditi's birthday is missed by her best guy friend for a date with Mehgan. She doesn't take it well.
- In The Deep Blue Sea, Rachel Weisz' character attempts suicide after her beau forgets hers.
- The Amazing Spider-Man 2: Max (the guy who will become Electro) has his birthday in the day we first see him. But nobody (in his workplace) seems to remember, or care, about it. He even is told to repair the building's electrical system the same day. He also throws a One-Person Birthday Party.
- In one of the Gossip Girl books, Eleanor Waldorf unwittingly schedules her wedding for Blair's birthday.
- Harry Potter has the Dursleys generally forget his birthday. In Chamber of Secrets, Dudley mocks Harry about it being his birthday and how his friends seem to have forgotten about it, since nothing has arrived for Harry in the (owl) post. Uncle Vernon and Aunt Petunia do seem to have forgotten about it, or are ignoring it, as they are too focused on Vernon's boss coming over for dinner and hoping to make a good impression.
- In one chapter of Winnie-the-Pooh, Pooh noticed that Eeyore seemed very depressed (more so than usual), only to find out no one took notice of his birthday.
- In Animorphs, Tobias (who is Shapeshifter Mode Locked as a hawk except for two-hour intervals) learns that he is supposed to meet with a lawyer to receive a letter from his biological father on his "next birthday." He is a bit embarrassed to admit that, like other aspects of his human life, he can't quite remember when it is.
- In The Great Gatsby, we have the big scene where all the secrets between Gatsby, Daisy and Tom are revealed. Afterwords, First-Person Peripheral Narrator Nick suddenly realizes that it's his thirtieth birthday, which, combined with the aforementioned drama, spurs on a low-key midlife crisis.
- The Secret Life of the American Teenager: Everyone forgets Amy's sixteenth birthday while she's in New York. In the next episode, her mom (played by Molly Ringwald) is horrified when she finds out they forgot Amy's birthday and laments, "Everyone forgot my sixteenth birthday and it stayed with me forever!" Amy is mildly irritated, but she quickly gets over it.
- Hannah Montana: In this case, Miley and Jackson actually did forget their father's birthday.
- The brothers invoke this trope twice on Jonas.
- In "Groovy Movies", they forget their mother's birthday.
- In "Forgetting Stella's Birthday", they forget Stella's birthday because a band executive came to interview them that day. It gets even worse when they try to make up for it by throwing a Slumber Party at the same exact time as the executive came back to interview them again.
- In Malcolm in the Middle, Hal does this to Lois, as his programmed watch didn't go off.
- In one episode of Married... with Children, the family decides to make tomorrow Seven's birthday since nothing is happening on that day. Turns out it is actually Al's birthday.
- During the beginning events of Kamen Rider Kuuga, both Yuusuke and his police partner Ichijo wind up forgetting their own birthdays in their fight against the Grongi, both birthdays happening in different episodes. This isn't to highlight just how tragic things are, but rather show that they have a lot in common.
- The pilot to Little Mermaid's Island has Sebastian worrying that Ariel and the others have forgotten his birthday. They haven't... except for Scuttle, at least.
- That Seventies Show has an episode where Red and Eric both forget Kitty's birthday until the very last minute, at which point they try to pass it off as a Not-So-Forgotten Birthday via Convenience Store Gift Shopping (which no, does not work). Hyde actually did remember and wished her a happy birthday, but didn't tell the others because "how would that be funny?" Ultimately they're forced to make it up to her by engaging in Kitty's most horrible hobby: square dancing.
- In the Aly & A.J. song "Potential Breakup Song" the singer's boyfriend forgot her birthday.
"It took too long for you to call back/And normally I would just forget that/Except for the fact it was my birthday/My stupid birthday"(...) "What kind of a boyfriend would forget that/Who would forget that?"
- A Garfield strip from September 25, 2015 has Jon discuss this as a reason why Liz was mad at him.
- Amnesia LATER: Ikki points out that Kent doesn't care much for his birthday and often forgets the importance of the date. When the heroine asks Kent to come over to her place on the 23rd under the pretense of just having a relaxing date watching movies, she's surprised to learn that he really doesn't associate that date with his birthday.
- In Bravest Warriors Danny built a Robo-Chris to make Chris jealous because he forgot Danny's birthday.
- God, the Devil and Bob: God forgets the Devil's birthday (and has apparently done this a lot), prompting the Devil to leave and take Evil with him. Bob ends up playing therapist to the two of them.
The Devil: I'm supposed to believe that he forgot my birthday? He's omniscient!
- The Simpsons
Homer: Oh, come on, tell us how we can make it up to you. Hey, pretend it's your birthday.Lisa: It is my birthday!Bart: That's the spirit!
- "Stark Raving Dad" takes place on Lisa's birthday and nobody remembers it. Bart is the only one Lisa complains about.
- It happens again in "Stark Raving Dad," after Homer and Bart accidentally destroy Lisa's room.
Homer: I can't believe I'm being mocked ... by my own family ... on my birthday!Bart: It's your birthday?Homer: Yeah, don't you remember? It's the same day as the dog's.Lisa: [gasps] Oh, Santa's Little Helper! It's your birthday?! We have to do something special! Yes we do!Homer: [muttering] Lousy lovable dog.
- Another quick joke, this time with Homer:
- Inverted in another episode. Barney is upset with everyone at Moe's for not remembering his birthday. Turns out they actually threw a birthday party for him at Homer's place, but he got so drunk, he blacked out and couldn't remember any of it. This, plus the video footage of what he's like when he is that drunk caused him to try and sober up.
- American Dad! had an episode called "1600 Candles" in which Roger anticipates his 1600th birthday, only to have it preempted by Steve's shenanigans. Of course it has the obligatory Sixteen Candles scene. Of course, as usual, Roger was being a complete Jerk Ass about it, effectively telling Stan and Francine that they should give up on Steve completely just so they can throw him exactly the kind of party he wants.
- Kim Possible: After being freaked out and then downright terrified by Shego's moodulator-induced mood swings from giddiness to weeping to fury, Drakken works up the nerve to ask "Did I forget your birthday? Is that what this is about?"
- Played for Laughs on South Park: the first Christmas Episode has a mid-credits scene with Jesus alone in his studio, having a One-Person Birthday Party.
- A Pup Named Scooby-Doo: In one episode, the gang questioned a suspect about a letter and he said it was an apology letter to his mother and he was asked if it was for forgetting her birthday. It wasn't.
- Inverted in Total Drama World Tour when Cody is the one who forgets his birthday. Sierra remembers, and even bakes him a cake after she finishes the challenge.
- Played straight in that Cody mentions his parents forgot his last birthday.
- Family Guy:
- In one episode Peter and Lois forget Meg's birthday. When Meg mentions wanting a party, they spend some time wondering what she wants a party for. They even consider that she's getting married, but cautiously dismiss it because they don't remember her bringing any guys around. It took Chris to remind them it's her birthday. They also completely forget what age she's turning when it's coming up. At one point, when they talk to her, they try using hints so they can learn her upcoming age without telling her outright. Unfortunately Meg is already aware of the whole thing, as is expected of the series Butt-Monkey.
- In another episode, there's a cutaway to Meg at her birthday party at a restaurant, where she's alone at a big table with a "HAPPY BIRTHDAY MEG" banner behind her. She asks a waiter for some more bread while she waits for everyone else to show up. The waiter tells her that she has eaten so much bread [while waiting] that they're going to have to start charging her for it.
- In the Bob's Burgers pilot, this is taken Up to Eleven when it is revealed that Bob routinely forgets not only his wife's birthday, but his own.
- An episode of Squirrel Boy has Rodney forgetting Andy's birthday. When Mr. Johnson tries to remind him of it, Rodney laughs it off saying that "Andy's birthday was 12 months ago".
- In the Phineas and Ferb episode "Mom's Birthday", Phineas and Ferb realize they had forgotten their mother's birthday when they wake up to Candace rehearsing her birthday song to Lind. Cue to references of previous episodes each of which Phineas reminds Ferb that they won't forget their mother's birthday, before he finally says "Is there something I am supposed to remember?" In "It's About Time".
- In the episode of Johnny Test where the title character refuses to take a bath, Dukey repeatedly makes reference to the fact that Johnny forgot his. Except he didn't; the bath refusal was all a plan to get Dukey an entire pool room with the works.
- In My Little Pony: Friendship Is Magic, the entire plot of "The Party of One" is caused by Pinkie forgetting about her own birthday. When her friends try to secretly prepare a birthday party for her, Pinkie mistakes their odd behavior as them not wanting to be friends with her anymore.
- Subverted in an episode of Teen Titans Go!. Beast Boy thinks his friends have forgotten his birthday. They haven't; they just loathe birthday parties and refuse to throw one.