The 26-year-old, who had been deemed surplus to requirements at the Rhein-Neckar Arena, has put pen to paper on a two-year contract with Frankfurt.
Manager Armin Veh told the club's official website: "We are delighted to have signed Stephan Schrock.
"We had already been keen on Stephan Schrock last season due to his ability to feature in various positions.
"It is a good thing that the transfer has finally gone through."
Schweinfurt-born Schrock has represented the Philippines eight times at senior international level.