Margaret Mary Nichols (born September 12, 1997) is an American former collegiate artistic gymnast. She was the ninth NCAA gymnast to complete a Gym Slam, the first to do so for Oklahoma, and the first NCAA gymnast to have achieved it twice.

In January 2018, Nichols came forward as one of the many victims sexually abused by former USA Gymnastics doctor Larry Nassar, starting when she was 15. Additionally Nichols revealed that it was her coach who initially reported Nassar and his abuse to the USA Gymnastics staff:

One day at practice, I was talking to my teammate, and brought up Dr. Nassar and his treatments. When I was talking to her, my coach overheard. I had never told my coach about these treatments. After hearing our conversation she asked me more questions about it and said it doesn't seem right ... so she did the right thing and reported this abuse to the USA Gymnastics staff.

On May 16, 2018, it was announced that Nichols and the other survivors would be awarded the Arthur Ashe Courage Award. Nichols' experience was highlighted in the Netflix documentary Athlete A, as well as the HBO documentary At the Heart of Gold.

In a column published March 27, 2020, Nichols stated that she would work as a student coach for the Sooners while completing her bachelor's degree and also indicated interest in sports broadcasting and writing a book. Her memoir, “Unstoppable!: My Journey from World Champion to Athlete A to 8-Time NCAA National Gymnastics Champion and Beyond”, was published on January 16, 2024.

As of 2024, she works as a certified personal trainer in South Padre Island, Texas. She also advocates for victims of abuse through her Maggie Nichols Foundation.