This research chapter explores the traditional interior design and architecture of the Asir region, the southwestern province of the Kingdom of Saudi Arabia bordering Yemen, and illustrates the role of nature in shaping the built environment therein. Ninety-five percent of land in Saudi Arabia is desert, and thus, the desert climate prevails with extremely high temperatures during the day and sudden temperature drops at night. With its rocky terrain, deep valleys and high mountain tops, the Asir region is an exception to this climatic tendency in the country, resulting in significantly different architectural forms and designs. Local building materials and practices of the region demonstrate high levels of craftsmanship while cultural influences are reflected in ornamentation, detailed design elements and use of vibrant colors, making Asir region a jewel in Saudi Arabia worthy of a study. Inspired from nature’s forms, functions, and principles, humankind has been mimicking nature for over three billion years. This process of biomimicry has enabled the realization of solutions to problems in the built environment. More so now than ever, there is an urge to optimize energy use, reduce waste and increase recycling, promote sustainable practices, and connect to nature. The present study is an attempt to demonstrate the correlation between nature and the built environment through biomimicry as evident in traditional Saudi Arabian interiors. The research methodology is based on the qualitative paradigm and includes literature review, precedent studies; observations of topography, environment, climate, and the built forms of the Asir region; visual data analysis of design and architecture of the Asir region; and discussions with local academics. The research concludes that biomimicry allows practical solutions to design and architecture problems.