The Colombian youngster has committed his future to the Seagulls by signing a five-year contract, although he is expected to spend the coming season gaining experience on loan at a European club.
Orozco broke into Cali's senior set-up at just 16 and has already established himself at the highest level in Colombia. He featured 24 times in the country's top division last season, underlining his rapid development.
Brighton have now moved to bring the promising midfielder to England, with the club viewing him as a long-term prospect.
Sporting director Mike Cave said: "We have identified Matias as an exciting young talent who we're really pleased to bring to the club.
"He has already got good experience in Colombia and we will now place him with a club on loan for the 2026/27 season so he can continue his development.
"We're looking forward to working with him and to helping him reach his potential."
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.
Manchester City have completed the signing of 22-year-old Allan from Palmeiras in a transfer that could eventually reach 34 million pounds.
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.
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.
