Let $G{L}_{n_1,\dots ,n_r}$ be a parabolic subgroup of the general linear group $G{L}_n$ over the prime field ${\mathbb{F}}_p$ of $p$ elements. A complete set of distinct irreducible modules for ${\mathbb{F}}_p[G{L}_{n_1,\dots ,n_r}]$ was explicitly constructed in [7]. In this paper, we use this construction to determine the contragredient dual module of each ${\mathbb{F}}_p[G{L}_{n_1,\dots ,n_r}]$-irreducible module and prove that its dimension can be computed via the dimensions of some ${\mathbb{F}}_p[G{L}_{n_i}]$-irreducible modules.