The theory of Whittaker functors for $G{L}_n$ is an essential technical tools in Gaitsgory’s proof of the Vanishing Conjecture appearing in the geometric Langlands correspondence. We define Whittaker functors for $G𝕊p_4$ and study their properties. These functors correspond to the maximal parabolic subgroup of $G𝕊p_4$, whose unipotent radical is not commutative.We also study similar functors corresponding to the Siegel parabolic subgroup of $G𝕊p_4$, they are related with Bessel models for $G𝕊p_4$ and Waldspurger models for $G{L}_2$.We...