City will pay 32m pounds up front, with a further 2m available through performance-related additions. Allan has agreed a five-year contract and will remain at the Etihad until the off-season of 2031.
"This is a surreal moment for me. Manchester City, with everything they have won over the past 15 years, are one of the most attractive clubs in the world for players. To be able to sit here today and say I have joined them is the proudest moment of my life," Allan told the club's official website.
"I love Palmeiras and always will - but the decision to come to City was an easy one. I want to be the best footballer I can be and the conversations I've had with the people at City so far has convinced me there isn't a better place for me to fulfil my ambitions.
"I want to promise the Manchester City fans I will give absolutely everything to make the most of this opportunity."
Primarily deployed on the right wing, the Brazilian offers considerable flexibility. He has also featured as an attacking midfielder, second striker and, on occasion, at full-back.
Allan leaves Palmeiras after recording nine goals and 12 assists in 96 senior appearances for the Brazilian club.
His arrival continues a direct pathway between Palmeiras and Manchester City. Gabriel Jesus made the same switch in 2017, before defender Vitor Reis followed in January 2025.
Marcus Rashford appears set to remain at Manchester United after an 18-month absence from the club, with Harry Maguire believing the forward can still play an important role this season.
Julian Alvarez's future remains unresolved with the transfer window entering its final hours, despite Atletico Madrid's deadline for a decision passing without clarity.
Brighton have secured the services of 18-year-old midfielder Matias Orozco from Deportivo Cali, with the transfer understood to be worth around 3.5 million pounds.
Emi Martinez made an instant impression on his Chelsea debut as Xabi Alonso's side held on for a 4-3 win over Brighton at Stamford Bridge.
