Using the method of spectral decimation and a modified version of Kirchhoff's Matrix-Tree Theorem, a closed form solution to the number of spanning trees on approximating graphs to a fully symmetric self-similar structure on ´ a finitely ramified fractal is given. Examples calculated include the Sierpinski ´ Gasket, a non-p.c.f. analog of the Sierpinski Gasket, the Diamond fractal, and the Hexagasket. For each example, the asymptotic complexity constant is found. Dropping the fully symmetry assumption, it is shown that the limsup and liminf of the asymptotic complexity constant exist. Calculating the number of spanning trees on the m-Tree fractal shows that the asymptotic complexity constant for this class of fractals has no upper bound.