Throughout North America, from the Archaic period (ca. 8000–1000 BC) to the present, Indigenous Peoples used turtle shell rattles in a variety of cultural contexts, including in ceremonies. As a material, turtle shells can be an abundant, accessible, and easily processed raw material, whose shape and size lends itself to be a musical instrument. Many Indigenous Peoples in North America have cosmological, foundational beliefs about turtles. These beliefs provide a greater understanding of why turtle shell rattles are incorporated into ceremonies and dances. Furthermore, they help explain why they are used to keep rhythm, which in turn provides a basis for spiritual energy and experience. This paper reviews the ethnographic, ethnohistoric, and archaeological records of turtle shell rattle music in the contiguous United States. Turtle shell rattles are related to spiritual concepts of sound and are culturally defined and contextualized. A comprehensive review of their use reveals insights into the musical knowledge of several ancient and historic communities.