This dissertation focuses on American Methodist and Presbyterian missionaries’ work in central Mexico between 1873–1914. It follows the growth of Protestantism in Mexico from an American missionary endeavor to an identity Mexican Protestants defended against the nation’s Catholic majority. The Protestant missionary experience in Mexico is an important missing piece in the history of American missionary work and Porfirian Mexico. While at first glance, missionaries’ work to convert and reform Mexican’s morality through education, temperance, and the medical mission may not seem unique, I contend that the anti-Protestant sentiments they found in Mexico from Catholics drove missionaries to align themselves with the Porfirian government’s agenda. Tracing missionaries’ work through newspapers, missionary records, and personal records shows that missionaries intertwined themselves with the Porfirian idea of order and progress to advance their work. Missionaries framed Protestantism and their work in education, temperance, and the medical mission as important to advancing the moderation of Mexico the Porfirian government endeavored. By becoming allies of the Porfirian government’s agenda, missionaries spread Protestantism throughout central Mexico despite opposition from Catholics. Mexicans who embraced Protestantism saw positive changes in their lives as missionaries supported their educational advancement. Mexican Protestants formed a Mexican Protestant community with missionaries’ aid throughout the Porfirian era, but the Mexican Revolution and, more significantly, the American Intervention in 1914 disrupted the community. This project frames 1914 as the end of the first era of Protestantism not because Protestantism in Mexico came to an end, but because at this juncture, we see a firm Mexican Protestant community that could survive despite Catholic opposition and political disruptions. More broadly, analyzing the development of the Mexican Protestant community in central Mexico between 1873–1914 is important to understand the diversity in Mexican identities and how the meaning of Mexicanness has been redefined over time.