  In this work we study the topological properties of the $G_2$ lattice gauge
theory by means of Monte Carlo simulations. We focus on the behaviour of
topological quantities across the deconfinement transition and investigate
observables related to the $\theta$ dependence of the free energy. As in
$SU(N)$ gauge theories, an abrupt change happens at deconfinement and an
instanton gas behaviour rapidly sets in for $T>T_c$.
