The 32-year-old left Tottenham Hotspur for an undisclosed fee after spending two years at the north London club.
Parker had fallen down the pecking order at White Hart Lane after Tottenham added centre midfielder players Paulinho and Etienne Capoue in the close season.
Parker has made more than 300 Premier League appearances, having also played for Charlton Athletic, Chelsea, Newcastle United and West Ham United. He has won 18 international caps.
"I'm delighted that Scott has joined us," Fulham manager Martin Jol said on the club website (www.fulhamfc.com).
"He's a midfielder who works tirelessly for his team and is a fantastic player both on and off the ball.
"It is wonderful to see a player of his stature playing for Fulham Football Club as he has shown his qualities in the Premier League and for the England team for many years."
Parker will be eligible for Fulham's first home match of the season against Arsenal on Saturday after their Premier League campaign began with a 1-0 win at Sunderland.
(Reporting by Toby Davis; Editing by John Mehaffey)
