History AdaptationPersonalityChange / GameOfThrones

* Sam. In the books, he's a complete ShrinkingViolet who improves only very gradually and insists, "It was the dragonglass that slew it, not me," while in the show he likes to brag up his accomplishments: "How many brothers can say they've killed a White Walker ''and'' a Thenn? I might be the first in history!" Similarly, in the books he's "almost as frightened of brothels as the haunted forest," while in the show he constantly [[CovertPervert goes on about girls]] (Grenn and Edd {{lampshade|Hanging}} this) and asks, "Don't you think it's a bit unfair, making us take our vows while they sneak off for a little Sally on the side?"

* Sam:
** In the books, he's a complete ShrinkingViolet who improves only very gradually and insists, "It was [[spoiler: the dragonglass]] that slew it, not me," while in the show he likes to brag up his accomplishments: "How many brothers can say they've killed a White Walker ''and'' a Thenn? I might be the first in history!"
** Similarly, in the books he's "almost as frightened of brothels as the haunted forest," while in the show he constantly [[CovertPervert goes on about girls]] (Grenn and Edd {{lampshade|Hanging}} this) and asks, "Don't you think it's a bit unfair, making us take our vows while they sneak off for a little Sally on the side?"

* Fat Walda is shy, demure and amenable unlike the jolly BigFun she is in the books.
* Sansa:
** The books never even imply that she was "awful" to Jon as they agree in "Book of the Stranger", only that they were never as close as Jon and Arya and that she correctly referred to him as a half-brother which, oddly enough, is something Littlefinger needs to remind her of in the same episode.
** In fact, despite the aloofness between them, in the books Jon recalls Sansa teaching him how to dance and talk to girls and Sansa thinks warmly of Jon in ''A Feast for Crows''. Moreover, this all comes across as an InformedFlaw within the show itself, as Sansa is never shown acting like this with Jon or even arguing with Arya about it.

* In the original books, Renly is frivolous, charismatic and entitled, with a love for the fashion and romance of knightly pursuits. He seeks the throne simply because he has the support to do so. In the show, Renly is the complete opposite: a serious and intelligent man who hates bloodshed and must be convinced to seek the throne because he'll make a better ruler.

* Tywin in the series never has a thought beyond what he needs to do to attain and keep power. In the show, we learn that he ''does'' have a softer side, at least with Arya. His true ruthlessness seems to be reserved for his own family and others he expects more of.

* The show's version of Tyrion Lannister may as well be an entirely different character than the one in the books.
** [[CharacterizationMarchesOn While the show initially presents him as cynical deadpan snarker,]] Tyrion later seems to go out of his way to be an all-around NiceGuy to everyone he meets. His biggest contributions stem less from his brilliance and more so from the emotional support he provides for others.
** Tyrion's book counterpart is every bit as ruthless, greedy, lustful, and power-hungry as the other members of House Lannister. He maintains a prodigious degree of cunning, revels in exerting power over others, has a massive ego, and is capable of committing acts of great cruelty to those that cross him. His PetTheDog moments are reserved for those close to him and fellow outcasts, for whom he has a soft spot due to his status as a dwarf.

* Shae: Shae from the books was a GoldDigger who was only interested in Tyrion for his money and betrayed him when she got a better offer from Cersei. In the show she's a HookerWithAHeartOfGold who genuinely loves Tyrion. She still betrays him, but in the show it's because she's a WomanScorned after Tyrion tried to BreakHerHeartToSaveHer. The show also makes her more violent, threatening and/or attacking several characters with knives.

* Shae:
** Shae from the books was a GoldDigger who was only interested in Tyrion for his money and betrayed him when she got a better offer from Cersei. In the show she's a HookerWithAHeartOfGold who genuinely loves Tyrion. She still betrays him, but in the show it's because she's a WomanScorned after Tyrion tried to BreakHerHeartToSaveHer.
** Also of note, there is her reaction upon being found by Tyrion in Tywin's bed after her betrayal. In the books, she desperately attempts to plead with Tyrion even as he strangles her to death, whereas her show counter-part immediately panics upon seeing Tyrion and grabs a knife, making his strangling of her more akin to self-defense.

* Brienne:
** She becomes more aggressive and brusque than her gentle and unfailingly kind WideEyedIdealist book counterpart, who recoils at the thought of killing and treats everyone around her with an unfailing fairness. In the show, possibly thanks to the writers age lifting her by close to a decade, she actively seeks vengeance over fulfilling her vows of protection and is considerably more bitter and cynical, harboring no delusions as to the state of Westeros, and projects a much colder exterior as a result — particularly when it comes to Davos and Melisandre, who she openly regards as opportunistic traitors.
** That being said, she's still bullheadedly honorable and rarely crosses over into being openly ''unkind'' — even when it comes to Podrick, whom she initially treats a mite harshly but ultimately takes under her wing after bonding with him and apologizing for her behavior.
** However, she still takes obvious pleasure in killing enemies, even if it's a wounded man who can't fight back, and gloating about it, while in the books Brienne has only ever killed in self-defense, and even though they were utterly vile people she never takes pleasure in it.
* Stannis also comes to mind. While he's a bit of a hardass in the books, the TV series turns him into a fanatic who sacrificed his own daughter. In the books he's more of a pragmatic atheist who isn't so willing to follow Melisandre, and is more conflicted about his actions.

* Bronn from the books is simply a thuggish ProfessionalKiller whom Tyrion employs as his bodyguard. In the show he's an affable, witty PunchClockVillain who genuinely becomes friends with Tyrion.

* An in-universe example with the play depicting Season 1:
** Joffrey is a well meaning but ineffective ruler.
** Cersei is kind and not at all involved in treason.
** Ned is a greedy buffoon.
** Tyrion is the villain responsible for everything.

* Tywin in the series never has a thought beyond what he needs to do to attain and keep power. In the series, we learn that he ''does'' have a softer side, at least with Arya. His true ruthlessness seems to be reserved for his own family and others he expects more of.

* Fat Walda is shy and demure, unlike the jolly BigFun she is in the books.

* In the books Sam's a complete ShrinkingViolet who improves only very gradually and insists, "It was [[spoiler: the dragonglass]] that slew it, not me," while in the show he likes to brag up his accomplishments: "How many brothers can say they've killed a White Walker ''and'' a Thenn? I might be the first in history!" Similarly, in the books he's "almost as frightened of brothels as the haunted forest," while in the show he constantly [[CovertPervert goes on about girls]] (Grenn and Edd lampshade this) and asks, "Don't you think it's a bit unfair, making us take our vows while they sneak off for a little Sally on the side?"

* The Waif is a {{Jerkass}} AlphaBitch who strikes, bullies, and denigrates Arya instead of the friendly and helpful mentor she is in the books.

* The books never even imply Sansa was "awful" to Jon as they agree in "Book of the Stranger", only that they were never as close as Jon and Arya and that she correctly referred to him as a half-brother which, oddly enough, is something Littlefinger needs to remind her of in the same episode. In fact, despite the aloofness between them, in the books Jon recalls Sansa teaching him how to dance and talk to girls and Sansa thinks warmly of Jon in ''A Feast for Crows''. Moreover, this all comes across as an InformedFlaw within the show itself, as Sansa is never shown acting like this with Jon or even arguing with Arya about it.

* Prince Doran Martell. In the show he wants to stop the CycleOfRevenge consuming his family. In the books, he's been plotting against the Lannisters despite Lord Tywin and The Mountain both being dead. His schemes has already claimed the life of one of his sons.

* Shae from the books was a GoldDigger who was only interested in Tyrion for his money and betrayed him when she got a better offer from Cersei. In the show she's a HookerWithAHeartOfGold who genuinely loves Tyrion. She still betrays him, but in the show it's because she's a WomanScorned after Tyrion tried to BreakHerHeartToSaveHer. Also of note, there is her reaction upon being found by Tyrion in Tywin's bed after her betrayal. In the books, she desperately attempts to plead with Tyrion even as he strangles her to death, whereas her show counter-part immediately panics upon seeing Tyrion and grabs a knife, making his strangling of her more akin to self-defense.

* Brienne becomes more aggressive and brusque than her gentle and unfailingly kind WideEyedIdealist book counterpart, who recoiles at the thought of killing and treats everyone around her with an unfailing fairness. In the show, possibly thanks to the writers age lifting her by close to a decade, she actively seeks vengeance over fulfilling her vows of protection and is considerably more bitter and cynical, harboring no delusions as to the state of Westeros, and projects a much colder exterior as a result — particularly when it comes to Davos and Melisandre, who she openly regards as opportunistic traitors. That being said, she's still bullheadedly honorable and rarely crosses over into being openly ''unkind'' — even when it comes to Podrick, whom she initially treats a mite harshly but ultimately takes under her wing after bonding with him and apologizing for her behavior. However she still takes obvious pleasure in killing enemies, even if it's a wounded man who can't fight back, and gloating about it, while in the books Brienne has only ever killed in self-defense, and even though they were utterly vile people she never takes pleasure in it.
* Stannis also comes to mind. While he's a bit of a hardass in the books, the TV series turns him into a fanatic who sacrificed his own daughter. In the books he's more of a pragmatic atheist who isn't so willing to follow Melissandre, and is more conflicted about his actions.

* Brienne becomes more aggressive and brusque than her gentle WideEyedIdealist book counterpart, actively seeking vengeance over fulfilling her vows of protection.

A lot of characters have had their [[AdaptationPersonalityChange personalities changed]] from the books:

* The books never even imply Sansa was "awful" to Jon as they agree in "Book of the Stranger", only that they were never as close as Jon and Arya and she correctly referred to him as a half-brother which, oddly enough, is something Littlefinger feels the need to remind her of in the same episode. Book!Jon Snow recalls that Book!Sansa taught him how to dance and talk to girls, and while Sansa was indeed distant to Jon and aloof, she does think warmly of him in ''A Feast for Crows''. In the show, moreover, this comes across as InformedFlaw, as she is never shown acting like this with Jon, or arguing with Arya on this matter, in the show.

* The books never even imply Sansa was "awful" to Jon as they agree in "Book of the Stranger", only that they were never as close as Jon and Arya and she correctly referred to him as a half-brother which, oddly enough, is something Littlefinger feels the need to remind her of in the same episode. However this comes across as InformedFlaw, as she is never shown acting like this in the show.

* The books never even imply Sansa was "awful" to Jon as they agree in "Book of the Stranger", only that they were never as close as Jon and Arya and she correctly referred to him as a half-brother which, oddly enough, is something Littlefinger feels the need to remind her of in the same episode.