Thermoplastic composites are trending because of their easy maintenance, recyclability, less processing time, lightweight, and chemical inertness. Carbon fiber-reinforced thermoplastic composites have high stiffness, strength, and toughness. Milling is required to make slots and pockets. Machining of composites is challenging due to inhomogeneity and differences in the nature of the reinforcement and matrix. Accurate machining ensures defect-free components. This study aims to determine how input parameters affect the milling process of in-house fabricated carbon fiber-reinforced thermoplastic composites. Three input parameters (feed rate, cutting depth, and spindle speed) were analyzed for the responses (machining force and delamination factor). The machining force and delamination factor were affected mainly by feed rate, with contributions of 71.73% and 51.19%, respectively. Spindle speed contributed 7.16% to the machining force and 18.04% to the delamination factor. Cutting depth contributed 12.57% and 25.85% to the machining force and delamination factor, respectively. This study offers a path to optimize the process parameters and control the machining quality during the milling of composite materials.