The Saudi Arabian side have announced the trainer's arrival from Porto less than a month after he clinched the Primeira Liga with the Dragoes on the final day of the season
Pereira spent two seasons in charge at the Dragao after replacing Andre Villas-Boas in June 2011, winning two league titles in the process.
A statement on Al Ahli's official website read that the 44-year-old will formally join the club on June 27 before starting pre-season two days later.
He will reportedly bring three assistants with him from Portugal to form part of his backroom staff.
Pereira succeeds Serbian Aleksandar Ilic as Al Ahli coach, who arrived for his second stint at the club in March but could only guide his side to fifth in the Saudi Pro League, 20 points behind winners Al-Fateh.