Wilder was born Jerome Silberman on June 11, 1933, in Milwaukee, Wisconsin, to a Russian Jewish family. He was the son of Jeanne (Baer) and William J. Silberman, a manufacturer and salesman of novelty items. Wilder first became interested in acting at age eight, when his mother was diagnosed with rheumatic fever and the doctor told him to "try and make her laugh."
At the age of 11, he saw his sister, who was studying acting, performing onstage, and the experience enthralled him. He asked her teacher if he could become his student, and the teacher said that if he was still interested at age 13, he would take Wilder on as a student. The day after Wilder turned 13, he called the teacher, who accepted him; Wilder studied with him for two years.
When Jeanne Silberman felt that her son's potential was not being fully realized in Wisconsin, she sent him to Black-Foxe, a military institute in Hollywood, where he was bullied and sexually assaulted, primarily because he was the only Jewish boy in the school, according to his own account. After an unsuccessful short stay at Black-Foxe, Wilder returned home and became increasingly involved with the local theater community. He performed for the first time in front of a paying audience at age 15, as Balthasar (Romeo's servant) in a production of Shakespeare's Romeo and Juliet. Gene Wilder graduated from Washington High School in Milwaukee in 1951.
Wilder was raised Jewish, but he held only the Golden Rule as his philosophy. In a book published in 2005, he stated, "I have no other religion. I feel very Jewish and I feel very grateful to be Jewish. But I don't believe in God or anything to do with the Jewish religion."
Wilder studied Communication and Theatre Arts at the University of Iowa, where he was a member of the Alpha Epsilon Pi fraternity. Following his 1955 graduation from Iowa, he was accepted at the Bristol Old Vic Theatre School in Bristol, England. After six months of studying fencing, Wilder became the first freshman to win the All-School Fencing Championship. Desiring to study Stanislavski's system, he returned to the US, living with his sister and her family in Queens, New York City. He enrolled at the HB Studio.