  By employing the general expression of temperature $T_{h}=|\kappa|/2\pi =
\frac{1}{2\pi \tilde{r}_{A}}(1-\frac{\dot{\tilde{r}}_{A}}{2H\tilde{r}_{A}})$
associated with the apparent horizon of a FRW universe and assuming a region of
FRW universe enclosed by the apparent horizon as a thermal system in
equilibrium, we are able to show that the generalized second law of
thermodynamics holds in Gauss-Bonnet gravity and in more general Lovelock
gravity.
