|“||Take care of everyone while I'm gone, ok?||”|
They met in their childhood and have always been close, even despite Caroline's former jealousy of Elena. They are also best friends with Bonnie Bennett. In season one, Caroline started to date Elena's ex-boyfriend, Matt, but suspected he was still in love with Elena until it finally became clear that he had moved on. When Caroline became a vampire, she and Elena grew closer while Bonnie temporarily ended her friendship with Caroline.
However, Elena and Caroline's relationship became tense after Elena broke up with Stefan, Caroline's best friend, following her transformation into a vampire, especially when she began a relationship with his brother, Damon. Elena was outraged when she discovered Caroline had told Stefan of her and Damon's relationship before they were ready. After Damon used the sire bond to have Elena turn her humanity off in order to help her deal with the death of her brother Jeremy, she confronted Caroline about her betrayal and bested her in a fight after Elena threatened her mother. In a lapse of pettiness, the still humanity-free Elena stole Caroline's prom dress, and Caroline eventually let Stefan and Damon proceed with their plan to torture her into regaining her humanity, though she was more reluctant to do so than Bonnie. After getting her humanity back, Elena, who was dealing with the return of the guilt and grief regarding the death of her brother, took some time before she was able to apologize to Caroline for her actions, but the two were able to rebuild their relationship over the summer before they left for college.
At Whitmore, Elena and Caroline shared a room together in the dorms, and they were later joined by Bonnie after she was made the Anchor to the Other Side and was able to interact with the living world again. Though Caroline continued to make snarky comments about Elena's relationship with Damon, Elena took it all in stride, even occasionally returning the snark by bringing up Caroline's off-and-on boyfriend Tyler. When Damon noticed Elena's uncharacteristic behavior after his transformation into an Augustine Vampire, it was Caroline who eventually put the pieces together and realized Elena had been possessed by Katherine using a Passenger spell just before her own body died of old age. After the Travelers cast the Magic Purification Spell, which destroyed the Other Side and indirectly resulted in the deaths of Bonnie and Damon, Caroline dropped out of school for a brief time, though she and Elena remained close friends. It was even Elena who convinced Caroline to return to Whitmore for their sophomore year and tried her best to help Caroline through her mother's illness and subsequent death.
However, the tables were turned when Caroline chose to turn off her humanity to deal with it, causing a reversal of roles where Elena was the one urging Caroline to come back and coming up with schemes to help speed up the process while Caroline fought back with violence. However, once Stefan managed to get through to Caroline and convince her to turn on her humanity, Caroline apologized to her best friends for her actions, which Elena accepted without question. Unfortunately, their reunion was short-lived, as the Gemini Coven leader Malachai Parker, desperate to get even with Bonnie and Damon for leaving him behind in the 1903 Prison World, put Elena into a magically-induced suspended animation that linked her sleep to Bonnie's life. As a result, Elena would only wake from her deep slumber if Bonnie died. Unwilling to let her friend die for her once again, Elena had one last reunion with Caroline and Bonnie using the former's vampire dream manipulation, during which time she made her two best friends promise to journal the next half-dozen decades so that when she awoke, she could read it all as though she were actually there. Caroline stayed true to this promise, and has continued to write a journal just for Elena in the months following Kai's curse.
In Season Eight, Elena and Caroline reunite after Elena awakens from her sleeping curse. They are currently sister-in-laws being Caroline married Stefan shortly before he died and Elena later married Damon after she woke up.
Throughout The Vampire Diaries Series
In Pilot, Caroline first came off as insensitive when she saw Elena Gilbert on the first day of school after Elena's parents had been killed in a car crash. During the back to school party, she found new guy Stefan Salvatore and flirtatiously invited him to go on a walk with her, but was insulted when he rebuffed her advances and showed an interest in Elena. She then told Bonnie Bennett that it was a competition, with Elena. Later Caroline starts dating with Damon, Stefan's brother, who begins to manipulate her and feed on her. Elena noticed the bruises and bite marks on Caroline for the first time and Caroline tried to brush Elena off. Elena confronted Damon, and afterwards he took Caroline away and started to feed on her, mad she had revealed something to Elena. He instantly became mysteriously weakened until Stefan arrived and revealed that he had spiked Caroline's drink with vervain, knowing that was the only way to stop him. Elena came to Caroline's aid and she broke down crying on Elena's shoulder as the stress of her brush with death finally got to her. Caroline grew closer to Elena's ex-boyfriend, Matt, and sought Elena's permission before she began dating him. Elena gave Caroline a vervain necklace to protect her. When Bonnie left town briefly following her grandmother's death, Elena and Caroline grew closer.
Caroline began acting insensitive toward Elena again when they competed for Miss Mystic Falls, however later encouraged her not to drop out and began encouraging her. When Caroline won, Elena was the first one she hugged and was very happy for her.
In I Was Feeling Epic Elena reunites with Caroline and tells her that Stefan got Caroline's message and confessed his everlasting love for Caroline before passing out.
- Both Caroline and Elena are vampires and were both turned by Damon's blood.
- They were both turned to serve some sort of purpose to an Original.
- They are best friends with Bonnie. They are also each best friends and wives with a Salvatore brother.
- Damon is Elena's best friend and husband.
- Stefan was Caroline's best friend and husband (before his death).
- They were briefly enemies in season four like they originally were in the novels.
- They have both dated Matt, Damon and Stefan.
- They both dated and had sex with Matt Donovan, Damon Salvatore, and Stefan Salvatore.
- They both had kissed Liam Davis.
- Their mothers Liz and Miranda were very close friends.
- In the books, Elena is more like Caroline in the series.
- Both of them have already kissed an Original.
- Both of them, at least once, turned off their humanity. Elena turned her humanity off in Season Four. Caroline turned her humanity off in Season Six.
- They seem to become enemies when either one shuts their humanity switch off.
- They both turned their humanities off due to the deaths of their loved ones.