To Kill a Mockingbird is a novel by Harper Lee published in 1960. It was immediately successful, winning the Pulitzer Prize, and has become a classic of modern American literature. The plot and characters are loosely based on Lee's observations of her family, her neighbors and an event that occurred near her hometown of Monroeville, Alabama, in 1936, when she was 10 years old.

Based on this passage, when did to kill a mockingbird come out? Let's give stream of consciousness first:
To answer this question, we should know that: To Kill a Mockingbird is a novel by Harper Lee published in 1960.
So, the final answer is 1960.