Claire Falkenstein (; July 22, 1908 – October 23, 1997) was an American sculptor, painter, printmaker, jewelry designer, and teacher, most renowned for her often large-scale abstract metal and glass public sculptures. Falkenstein was one of America's most experimental and productive 20th-century artists.
Falkenstein relentlessly explored media, techniques, and processes with uncommon daring and intellectual rigor. Though she was respected among the burgeoning post–World War II art scene in Europe and the United States, her disregard for the commodification of art coupled with her peripatetic movement from one art metropolis to another made her an elusive figure.
Falkenstein first worked in the San Francisco Bay Area, then in Paris and New York, and finally in Los Angeles. She was involved with art groups as radical as the Gutai Group in Japan and Un Art Autre in Paris and secured a lasting position in the vanguard, which she held until her death in 1997.
An interest in Einstein's theories of the universe inspired Falkenstein to create sculptures from wire and fused glass that explored the concept of infinite space. Falkenstein's current reputation rests on her sculpture, and her work in three dimensions was often radical and ahead of her time.