Recent reports have suggested that the Toffees are interested in the 22-year-old, as are Marseille and Sporting Lisbon.
The Algerian told Sky Sports News: "There is interest from clubs but I will decide at the end of the season.
"Everton? I have heard about that in the papers. They are a very good team and a big club so it is flattering.
"Let's wait and see if it is real interest at the end of the season. Marseille would also be fantastic but let's wait and see."
Ghilas has scored 11 goals in Portugal's Primera Liga so far this season.