Reading boss McDermott welcomes new coach Anastasiou from Ajax
The 39-year-old will remain at the club until at least the end of the season.
Royals boss Brian McDermott said: "Yannis is joining our coaching team and brings great experience, he had a fantastic playing career as well as being coach at a number of top sides across Europe.
"We first met at a Pro License course and he is a good guy, he speaks five languages and is a very positive character to have around the place.
"He will be able to work on individual aspects with players, he's here until the end of the season in the first instance and will add to the staff we already have."