Well, to make a long story short, Winona Ryder is not Jewish! (though she considers herself Jewish)
Since Winona Ryder's mother is not Jewish, and in Judaism one's religion is based on one's mother's religion, then that makes her also not Jewish (though once again, she DOES consider herself to be Jewish). Though she is not Jewish, Her father is Jewish, which makes her in some views half Jewish...
Winona Ryder (who's full birth name is Winona Laura Horowitz) was born on October 29, 1971 in Olmsted County, Minnesota, U.S..
She is known for her work with some of the most famous cult directors of the 90's like Tim Burton and Jim Jarmusch.