This study deals with the time domain (TD) diffraction phenomenon related to a penetrable acute-angled dielectric wedge. The transient diffracted field originated by an arbitrary function plane wave is evaluated via a convolution integral involving the TD diffraction coefficients, which are determined here in closed form, starting from the knowledge of the frequency domain counterparts. In particular, the inverse Laplace transform is applied to the uniform Asymptotic physical optics diffraction coefficients valid for the internal region of the wedge and the surrounding space. Diffraction by penetrable wedges in the TD framework is a challenging problem from the analytical point of view, and no other expressions are available in closed form for the diffraction coefficients associated with the considered problem.