In this paper we briefly review our finding about the effects of bound
ary conditions and lattice shapes on scaling functions in critical phe
nomena. We present new examples to show that different boundary condit
ions and lattice shapes may give quite different scaling functions for
lattice phase transition models, but they give consistent critical po
int, critical exponents, and thermodynamic order parameter from renorm
alization group calculations. We also review our recent results about
the universal scaling functions for bond and site percolations on plan
ar lattices with different boundary conditions and lattice shapes.