Color is one of the most powerful and often underestimated tools in interior design. In contemporary commercial environments—restaurants, retail spaces, offices, and hospitality interiors—color functions as a psychological and physiological stimulus that shapes how occupants feel, decide, and behave. This review paper investigates the psychological impacts of color in commercial interior spaces, neuroscience, and interior design theory. The study employs a qualitative, literature-based methodology, synthesizing peer-reviewed sources, and comparative case studies. The scientific basis of color perception—retinal cone stimulation, visual cortex activation, limbic system engagement, and autonomic nervous system responses—forms the foundational framework. Key findings confirm that warm colors (red, orange, yellow) increase arousal, appetite, and impulsive behavior, making them suited to food service and retail environments. Cool colors (blue, green) promote calmness, focus, and restoration, rendering them effective in offices and hospitality spaces.