Composite materials have proven their applicability for various structural components. Excellent properties of glass fiber reinforced plastic (GFRP) composite materials have presented GFRP composites for potential applications in aerospace and automobile-related industries. Drilling is an important operation for composite structures during final assembly. This paper investigates the factors affecting delamination in GFRP composite during the drilling process. Drill speed and feed rate are selected two parameters affecting delamination during the drilling process. The response surface methodology approach has been used for experimental design and analysis of variance. Delamination was evaluated at the entry, middle, and exit positions of the hole. An attempt has been made to optimize the speed and feed rate for minimization of delamination at the three positions using grey relational analysis. The results of this work will help in selecting an optimum level of speed and feed rate to minimize delamination at the entry, middle, and exit positions of the hole to improve quality of the drilled hole.