The Nilo-Saharan language family is a proposed African language family stretching from Algeria to Tanzania, encompassing over 200 languages and 70 million speakers. It was first proposed in 1963 by Joseph Greenberg in The Languages of Africa. Within this book, Greenberg sorted all the languages of continental Africa into four major language families: Afro-Asiatic, Niger-Congo, Khoisan, and Chari-Nile. Additionally, he identified six minor language groups and isolates, one of which, Kordofanian, was combined with Niger-Congo, while the other five, Songhai, Saharan, Maban, Coman, and Fur, were all combined with Chari-Nile to form the Nilo-Saharan family. In the past sixty years, this initial proposal has changed shape, with many of the family’s interior groupings being challenged, while the family at large continues to be used by linguists today. However, it is not a family without controversy, as Greenberg’s tendency to group together disparate languages from across the continent led to it being labeled a “wastebasket phylum” by Campbell and Poser, in which Greenberg could toss in all the “leftover languages” not accounted for within Africa’s more established families. The goal of my project is then to analyze and synthesize 60 years of academic inquiry into a comprehensive and defendable theory of the Nilo-Saharan languages and their relations, addressing both the groupings within the family and the validity of the family as a unified whole, all while utilizing linguistic techniques such as mass comparison and lexicostatistics, which use basic vocabulary to determine potential relationships between languages via the presence of cognates. By postulating an evidence-based thesis on the nature of the Nilo-Saharan languages, I hope to offer insight into the often overlooked field of African linguistics, a fundamental filament of the world’s linguistic fabric.