  We consider N=1 F-theory and Type IIB orientifold compactifications and
derive new \alpha' corrections to the four-dimensional effective action. They
originate from higher derivative corrections to eleven-dimensional supergravity
and survive the M-theory to F-theory limit. We find a correction to the Kahler
moduli depending on a non-trivial intersection curve of seven-branes. We also
analyze a four-dimensional higher curvature correction.
