Susan Keating Glaspell (July 1, 1876 – July 28, 1948) was an American playwright, novelist, journalist and actress. With her husband George Cram Cook, she founded the Provincetown Players, the first modern American theatre company.

First known for her short stories (fifty were published), Glaspell is known also to have written nine novels, fifteen plays, and a biography. Her 1930 play Alison’s House earned her the Pulitzer Prize for Drama.

Since the late 20th century, critical reassessment of women’s contributions has led to renewed interest in her career and a revival of her reputation. In the early 21st century Glaspell is today recognized as a pioneering feminist writer and America’s first important modern female playwright. Her one-act play Trifles (1916) is frequently cited as one of the greatest works of American theatre.