This article is concerned with a Kuramoto–Sivashinsky-Korteweg-de Vries equation in a bounded interval. The equation as well as one of the boundary conditions are supposed to be the subject of the presence of a parameter
. Moreover, this specific boundary condition has a time-delay effect. As
tends to zero, we show that one can obtain the findings of [4,58] concerning two Korteweg–de Vries equations. Indeed, we are able to retrieve the well-posedness and stability results for the Korteweg–de Vries problem without delay [58] and with delay [4] under the same conditions, as a singular limit of the Kuramoto–Sivashinsky equation with delay. The proof is based in the well-known Galerkin method together with the multiplier technique.