  We interpret the 750~GeV diphoton excess recently found in the 13~TeV LHC
data as a singlet scalar in an extra dimensional model, where one extra
dimension is introduced. In the model, the scalar couples to multiple
vector-like fermions, which are just the KK modes of SM fermions. Mediated by
the loops of these vector-like fermions, the $\phi$ effective couplings to
gluons and photons can be significantly large. Therefore, it is quite easy to
obtain an observed cross section for the diphoton excess. We also calculate the
cross sections for other decay channels of $\phi$, and find that this
interpretation can evade the bounds from the 8~TeV LHC data.
