This chapter introduces the theoretical and philosophical underpinnings of Sensible Design, presenting it as a transformative design methodology situated at the intersection of neuroscience and neurodiversity, while drawing on disability studies, sensory design, and Universal Design (UD). It positions Sensible Design as a framework for environmental design that prioritizes human sensory experience, well-being, and belonging. It begins by questioning conventional design practices, challenging the field to move beyond compliance, aesthetics, and efficiency toward empathetic, multisensory, and human-centered approaches. By distinguishing between sensory profiles, preferences, and priorities, the chapter proposes a novel model for understanding individual sensory identities. Drawing from disability studies and the social model of disability, it critiques the dominant medicalized framing of neurodivergence and calls for inclusive environments that honor diverse sensory needs. The chapter also extends UD by integrating sensory wellness, advocating for spaces that actively support the cognitive, emotional, and functional flourishing of all users. Through this foundation, Sensible Design emerges not as a trend but as a necessary evolution of practice and research—a movement for shaping inclusive environments that center lived experience, embrace diversity, and foster collective resilience.