Gibbs' overshoot refers to the persistent discrepancy between a Fourie
r series' approximation and actual values near a functional discontinu
ity. Here this phenomenon is generalized to a fractal discontinuity on
a trial function. Analytic results support the conclusion that fracta
l dimension can parameterize the Gibbs' overshoot on an example sawtoo
th with a fractal distribution of discontinuous depths. Simulations co
nfirm this finding on a fractal Brownian walk and the devil's staircas
e. Results indicate that the overshoot arises on a fractal not as much
from any general ruggedness, but more from the fractal discontinuity
directly.