The Bundesliga champions confirmed the extension on Thursday, ending speculation that had been running since December, when Kiala's father was reported to have met with representatives of Chelsea and Manchester City in London.
Both Premier League clubs had been credited with an interest in the 17-year-old, according to Bild, but will now go without him.
Kiala's previous deal had been due to expire in 2027, meaning Bayern have added three years and removed any uncertainty over his long-term future well before it became pressing.
Born in Berlin, he joined Bayern's academy from Hertha BSC in 2024 and made his first-team debut at the age of 16, coming off the bench in a 4-0 win over Heidenheim last December to become one of the youngest players ever to appear for the club in the Bundesliga.
His progress was interrupted in February by a torn syndesmosis ligament, but Kiala has since returned to full fitness. Bayern's academy staff have long regarded him as one of the standout talents to come through the club's youth ranks in recent years, and the new deal underlines their determination to build the first team around homegrown prospects rather than risk losing them to rivals abroad.
With interest from two of the Premier League's biggest clubs now closed off, Bayern will hope Kiala can continue his development at Säbener Strasse and eventually establish himself as a regular in the club's back line.
The extension follows a familiar pattern at Bayern, who have made a point in recent seasons of moving quickly to secure promising academy graduates before external interest can escalate into a serious transfer threat.
Kiala's rise has been rapid: as recently as last autumn he was still turning out for the club's under-19 side before a string of impressive performances in training persuaded head coach Vincent Kompany to hand him his senior bow against Heidenheim.
Bayern Munich's hierarchy is understood to see him as a long-term option in the heart of defence, with his physical profile and composure on the ball marking him out even at academy level.