The 24-year-old makes the permanent switch following two years in Glasgow.
The 24-year-old made the move permanent after two years in Glasgow after spending one season on loan from Benfica before signing a permanent deal.
Jota helped Celtic to two league titles during his time at the club, scoring 27 goals in all competitions over two years.
He follows a string of high-profile players to join the Saudi Pro League and becomes Al-Ittihad’s third signing of the summer, following the signings of former Real Madrid forward Karim Benzema and ex-Chelsea midfielder N’Golo Kante for the club.
After signing, Celtic wrote on the club’s website: “During his time at the Hoops, Jota won two league titles as well as winning medals in both the Scottish and League Cups.
“Everyone at Celtic Football Club wishes Jot every success in his future career.”