The story is set primarily in the Sword Coast in western Faerûn, encompassing a forested area that includes the Emerald Grove, a druid grove dedicated to the deity Silvanus; Moonrise Towers and the Shadow-Cursed Lands, which are covered by an unnatural and sentient darkness that can only be penetrated through magical means; and Baldur's Gate, the largest and most affluent city in the region, as well as its outlying suburb of Rivington.

[15] The game is fully narrated by voice actress Amelia Tyler, who acts as the Dungeon Master, describing the world and the player's actions throughout the story.

They include Lae'zel (Devora Wilde), a githyanki fighter; Shadowheart (Jennifer English), a half-elf cleric; Astarion (Neil Newbon), a high elf vampire rogue; Gale (Tim Downie), a human wizard; Wyll (Theo Solomon), a human warlock; and Karlach (Samantha Béart), a tiefling barbarian.

[20] The primary antagonists of the game are the Absolute (Cissy Jones), and her three chosen followers General Ketheric Thorm (J. K. Simmons), Lord Enver Gortash (Jason Isaacs), and Orin the Red (Maggie Robertson).

Additional major characters include: Withers (Stephen Boxer), a mysterious undead entity who supports the player in camp; Raphael (Andrew Wincott), a devil with a penchant for making deals; Elminster (Crispin Redman), a renowned wizard and mentor to Gale; Auntie Ethel (Rena Valeh), a fussy trader of potions and sundries; Bhaal (Doug Cockle), the God of Murder; Mystra (Jane Perry), Goddess of Magic; Shar, Goddess of Darkness; Volo (Stephen Hogan), an unlucky writer; Mizora (Tamaryn Payne), a manipulative devil with a connection to Wyll; Isobel (Mia Foo), a half elf cleric working with Jaheira; Dame Aylin (Helen Keeley), Isobel's partner and an aasimar paladin; Ulder Ravengard (Chris Jarman), Wyll's father and Duke of Baldur's Gate; Kith'rak Voss (Richard Cotton), a githyanki knight; Dammon (Frazer Blaxland), a tiefling blacksmith, and The Emperor (Scott Joseph), a mind flayer with a key role in the main story.

They are saved from the tadpoles' overwhelming psychic force by a "Dream Visitor" inside Shadowheart's mysterious prism, a device that is sought after by the githyanki.

The protagonist then becomes involved in the fate of the Emerald Grove, where local druids and tiefling refugees face off against the goblin horde that worships a cult of the "Absolute".

Once the party either sacks or saves the grove, they travel through the mountains or the Underdark to reach Moonrise Towers, a cultist stronghold, in search of a new cure.

The protagonist seeks sanctuary from the curse around Moonrise Towers in a tavern called the Last Light, held by a group of tiefling refugees, Flaming Fist conscripts and Harpers.

Through their Netherstones and a mysterious crown, the triumvirate collectively controls the Absolute, revealed to be an Elder Brain, the ultimate form of the illithid race, and seeks to rule the Sword Coast by manipulating everyone infected with a tadpole.

The protagonist arrives at Baldur's Gate as Gortash and Orin attempt to pit them against the other, while the companions find closure for their personal quests.

It is revealed that the "Dream Visitor" is, in fact, a visage taken by a renegade illithid called the Emperor, who resides within the prism and oversees the imprisonment of a powerful githyanki, Orpheus.

After defeating the Elder Brain, the protagonist can choose to either kill it and every illithid tadpole with it, ending the threat forever, or betray their comrades and rule as the Absolute.

The game's success led to a sequel, Baldur's Gate II: Shadows of Amn, and its expansion pack, as well as the Icewind Dale series and Planescape: Torment.

After the release of Neverwinter Nights 2, Obsidian Entertainment founder Feargus Urquhart unsuccessfully approached Atari to develop a sequel to Baldur's Gate.

[25][26] Larian Studios were interested in making a sequel in the Baldur's Gate series for some time, having first approached Wizards of the Coast after their release of Divinity: Original Sin around 2014.

[48] A patch in December 2023 added two new difficulty modes, quality of life enhancements, and a new playable epilogue containing over 3,500 new dialogue lines.

[55] Critics praised the quality of the writing, including the detailed depiction of the Dungeons & Dragons setting of Faerûn;[78][80][81] the intertwined storylines enabling alternate story moments and a large degree of player freedom;[78][81] and the characters, particularly companions, that feel interesting and memorable.

[81][additional citation(s) needed] The Dark Urge character origin received particular critical acclaim, with reviewers drawing parallels to the independent storyline in Fallout: New Vegas and the Malkavian clan in Vampire: The Masquerade — Bloodlines.

[84] Polygon's Cass Marshall, among other critics, praised how the internal struggle with intrusive thoughts and their consequences added narrative depth.

[85] In TechRadar, Cat Bussell noted that the manifestation of dark urges through dialogue options and appearances of Sceleritas Fel created a distinct sense of loss of control, comparable to horror game experiences.

[86] GamesRadar+'s Jasmine Gould-Wilson observed that the character's integral connection to the plot reinforced its perceived canonicity and heightened the impact of player choices.

[80] Alex Battaglia of Eurogamer praised the game's performance on PC, and added that "Baldur's Gate 3 launches in a polished state with no game-breaking issues, shaming the technical quality of other big AAA releases".

[95] By 26 February 2024 the Director of Publishing at Larian, Michael Douse, said the game had sold "way over 10 [million] in a very short space of time".