Antibodies or antigen-binding fragments thereof are engineered to bind Transforming Growth Factor-ß (TGFß). TGFß-isoform selective antibodies or antigen-binding fragments thereof may selectively bind human TGFß1, compared to human TGFß2 and human TGFß3, or may selectively bind human TGFß3, compared to human TGFß1 and human TGFß2. The design of the antibodies or antigen-binding fragments thereof is facilitated by a co-crystal structure of a recombinant Fab fragment of GC1008 bound to TGFß2 and by another co-crystal structure of the scFv version of GC1008 bound to TGFß1.