Nancy "Nettie" Fowler (1835–1923) was an American philanthropist. She was also a prominent member of the McCormick family
She was born in 1835 and was raised by her grandmother in Clayton, New York. She attended Emma Willard School in Troy, New York. She met Cyrus Hall McCormick in 1857 while visiting friends in Chicago. They were married in 1858. While Cyrus was working out a controversy involving his patent of the reaper they lived in Washington, DC. She had a keen business sense and became a great asset to her husband. Nettie became his financial counselor and oversaw many of the business affairs. She toured expositions in McCormick's interest making contacts for the company. In 1871, the Great Chicago Fire destroyed McCormick Harvesting Machine Company. But, despite Cyrus' thoughts of retirement afterward, Nettie insisted on rebuilding even larger than before.
The McCormicks provided $100,000 to bring the Hanover Seminary to Chicago. The school was renamed McCormick Theological Seminary soon after Cyrus's death in 1884. Nettie continued to fund buildings, endowing professorships, and scholarships at the seminary even after his death. Nettie donated to over forty schools and colleges. At the time of her death she left more than $1 million to be divided among various institutions. At Tusculum College, one of the many colleges Nettie supported, every September 13 observes Nettie Fowler McCormick Service Day. On this day students perform community service in her honor. She is buried at Graceland Cemetery in Chicago.