Helen Levitt (August 31, 1913 – March 29, 2009) was an American photographer and cinematographer. She was particularly noted for her street photography around New York City. David Levi Strauss described her as "the most celebrated and least known photographer of her time."

Levitt was born in Bensonhurst, Brooklyn, New York, the daughter of May (Kane), and Sam Levitt. Her father and maternal grandparents were Russian Jewish immigrants. She went to New Utrecht High School but dropped out in 1931.

She began photography when she was eighteen and began working for J. Florian Mitchell, a commercial portrait photographer in the Bronx, where she learned how to develop photos in the darkroom. She also attended many classes and events hosted by the Manhattan Film and Photography League, and got acquainted with the work of Henri Cartier-Bresson at the Julien Levy Gallery, who she was able to meet through the league. His work became a major influence for her photography as it inspired her to change from her more journalistic and commercial approach to photography to a more personal one.

In 1936, she purchased a 35 mm rangefinder camera. While teaching art classes to children in 1937 for New York City's Federal Art Project, Levitt became intrigued with the transitory chalk drawings that were part of the New York children's street culture of the time. She began to photograph these chalk drawings, as well as the children who made them for her own creative assignment with the Federal Art Project. They were ultimately published in 1987 as In the Street: Chalk Drawings and Messages, New York City 1938–1948.

She continued taking street photographs in Manhattan, mainly in Spanish Harlem but also in the Garment District and on the Lower East Side. During the 1930s to 1940s, the lack of air conditioning meant people were outside more, which invested her in street photography. Her work was first published in Fortune magazine's July 1939 issue. The new photography section of the Museum of Modern Art, New York included Levitt's work in its inaugural exhibition in July 1939. In 1941, she visited Mexico City with Alma Mailman, then wife of author James Agee, and took photos in the streets of Tacubaya, a working-class suburb. In 1943, Nancy Newhall curated her first solo exhibition Helen Levitt: Photographs of Children with photographs from Harlem and Mexico City.

In 1959 and 1960, she received two grants from the Guggenheim Foundation for her pioneering work in color photography. In 1965 she published her first major collection, A Way of Seeing. Much of her work in color from 1959 to 1960 was stolen in a 1970 burglary of her East 12th Street apartment. The remaining photos, and others taken in the following years, can be seen in the 2005 book Slide Show: The Color Photographs of Helen Levitt. A second solo exhibit, Projects: Helen Levitt in Color, was held at the Museum of Modern Art, New York in 1974. Her next major shows were in the 1960s; Amanda Hopkinson suggests that this second wave of recognition was related to the feminist rediscovery of women's creative achievements. In 1976, she was a Photography Fellow of the National Endowment for the Arts.

Levitt lived in New York City and remained active as a photographer for nearly 70 years. However, she expressed lament at the change of New York City scenery: "I go where there's a lot of activity. Children used to be outside. Now the streets are empty. People are indoors looking at television or something."

During WWII, Levitt served as assistant film editor at the Office of Inter-American Affairs, producer-editor of stock footage film Here Is China (1940), and as assistant film editor at the Office of War Information Overseas Branch in New York City 1944–45.