The striker has been a free agent since leaving Manchester United in the summer at the end of his contract after spending 9 years with the English side.
Fans are expected to greet him upon his arrival at Athens International Airport later tonight in what is a huge deal for the club.
The 28-year-old has been linked with a number of clubs after leaving United including Brazilian side Flamengo, Lille, Atalanta, Marseille and Besiktas but has now signed a three-year deal as he looks to lift the Greek title.
Martial is said to be in line to earn £2.5million per season with AEK and is the most lucrative deal in AEK's history as the league continues to fill up with stars from around the world.
The winger will link up with ex-Tottenham star Erik Lamela, former Watford players Roberto Pereyra and Nordin Amrabat, as well as ex-Brentford goalkeeper Thomas Strakosha in a side that currently sits top of the table.