The former Aston Villa and West Ham United player has been without a club since leaving Wolfsburg in the summer.
Everton confirmed the deal this afternoon and are hopeful that because the contract was signed before today's midday deadline he will be available to David Moyes for Sunday's Premier League clash at Queens Park Rangers.
Hitzlsperger managed only two league starts in the Bundesliga last season after he suffered a knee injury.
In a bid to earn a deal at Goodison Park, Hitzlsperger has been training with the Toffees and played 90 minutes for the Under-21 side on 8 October.
Moyes has moved for the 30-year-old after it was confirmed that Marouane Fellaini will miss the next three weeks with a knee injury, while he is also without Darron Gibson with a thigh injury.
Hitzlsperger has earned 52 caps for his country and made 208 league appearances since his senior debut for Aston Villa in January 2001.