  In this paper, we investigate quasinormal modes of scalar and electromagnetic
fields in the background of Einstein--scalar--Gauss--Bonnet (EsGB) black holes.
Using the scalar and electromagnetic field equations in the vicinity of the
EsGB black hole, we study nature of the effective potentials. The dependence of
real and imaginary parts of the fundamental quasinormal modes on parameter $p$
(which is related to the Gauss--Bonnet coupling parameter $\alpha$) for
different values of multipole numbers $l$ are studied. We analyzed the effects
of massive scalar fields on the EsGB black hole, which tells us the existence
of quasi--resonances. In the eikonal regime, we find the analytical expression
for the quasinormal frequency and show that the correspondence between the
eikonal quasinormal modes and null geodesics is valid in the EsGB theory for
the test fields. Finally, we study grey-body factors of the electromagnetic
fields for different multipole numbers $l$, which deviates from Schwarzschild's
black hole.
