Rachel Louise Carson (May 27, 1907 – April 14, 1964) was an American marine biologist and conservationist whose book Silent Spring and other writings are credited with advancing the global environmental movement.

Carson began her career as an aquatic biologist in the U.S. Bureau of Fisheries, and became a full-time nature writer in the 1950s. Her widely praised 1951 bestseller The Sea Around Us won her a U.S. National Book Award, recognition as a gifted writer, and financial security. Her next book, The Edge of the Sea, and the reissued version of her first book, Under the Sea Wind, were also bestsellers. This sea trilogy explores the whole of ocean life from the shores to the depths.

Late in the 1950s, Carson turned her attention to conservation, especially environmental problems that she believed were caused by synthetic pesticides. The result was Silent Spring (1962), which brought environmental concerns to an unprecedented share of the American people. Although Silent Spring was met with fierce opposition by chemical companies, it spurred a reversal in national pesticide policy, which led to a nationwide ban on DDT and other pesticides, and it inspired a grassroots environmental movement that led to the creation of the U.S. Environmental Protection Agency. Carson was posthumously awarded the Presidential Medal of Freedom.

A variety of groups ranging from government institutions to environmental and conservation organizations to scholarly societies have celebrated Carson's life and work since her death. Perhaps most significantly, on June 9, 1980, Carson was awarded the Presidential Medal of Freedom, the highest civilian honor in the United States. A 17¢ Great Americans series postage stamp was issued in her honor the following year; several other countries have since issued Carson postage as well.

Carson's birthplace and childhood home in Springdale, Pennsylvania — now known as the Rachel Carson Homestead—became a National Register of Historic Places site, and the nonprofit Rachel Carson Homestead Association was created in 1975 to manage it. Her home in Colesville, Maryland where she wrote Silent Spring was named a National Historic Landmark in 1991. Near Pittsburgh, a 35.7 miles (57 km) hiking trail, maintained by the Rachel Carson Trails Conservancy, was dedicated to Carson in 1975. A Pittsburgh bridge was also renamed in Carson's honor as the Rachel Carson Bridge. The Pennsylvania Department of Environmental Protection State Office Building in Harrisburg is named in her honor. Elementary schools in Gaithersburg, Montgomery County, Maryland, Sammamish, Washington and San Jose, California were named in her honor, as were middle schools in Beaverton, Oregon and Herndon, Virginia (Rachel Carson Middle School), and a high school in Brooklyn, New York.

Between 1964 and 1990, 650 acres (3 km2) near Brookeville in Montgomery County, Maryland were acquired and set aside as the Rachel Carson Conservation Park, administered by the Maryland-National Capital Park and Planning Commission. In 1969, the Coastal Maine National Wildlife Refuge became the Rachel Carson National Wildlife Refuge; expansions will bring the size of the refuge to about 9,125 acres (37 km2). In 1985, North Carolina renamed one of its estuarine reserves in honor of Carson, in Beaufort.

Carson is also a frequent namesake for prizes awarded by philanthropic, educational and scholarly institutions. The Rachel Carson Prize, founded in Stavanger, Norway in 1991, is awarded to women who have made a contribution in the field of environmental protection. The American Society for Environmental History has awarded the Rachel Carson Prize for Best Dissertation since 1993. Since 1998, the Society for Social Studies of Science has awarded an annual Rachel Carson Book Prize for "a book length work of social or political relevance in the area of science and technology studies."

Rachel Carson’s Silent Spring was first published in three serialized excerpts in the New Yorker in June of 1962. The book appeared in September of that year and the outcry that followed its publication forced the banning of DDT and spurred revolutionary changes in the laws affecting our air, land, and water. Carson’s passionate concern for the future of our planet reverberated powerfully throughout the world, and her eloquent book was instrumental in launching the environmental movement. It is without question one of the landmark books of the twentieth century.