The Hollyhock House is a house museum at Barnsdall Art Park in the East Hollywood neighborhood of Los Angeles, California, United States. The house, designed by the architect Frank Lloyd Wright for the heiress Aline Barnsdall, is named for the hollyhock-inspired motifs in its design. The main house, incorporating elements from multiple architectural styles, consists of three wings around a central courtyard. It was built alongside two guesthouses called Residence A and B, a garage building, the Schindler Terrace, and the Spring House. Rudolph Schindler, Richard Neutra, and Wright's son Lloyd Wright helped design the main house and the other buildings.

Barnsdall had tentatively planned to build a theatrical complex since 1915, and she acquired the site, then known as Olive Hill, in 1919. She hired Wright to design the complex, plans for which were revised multiple times. The house and its outbuildings, completed in 1921, were the only parts of the complex to be built, though they were not used for theatrical purposes. The Los Angeles city government acquired Hollyhock House and some of the surrounding land in 1927, establishing Barnsdall Park and leasing the main house to the California Art Club for 15 years. Barnsdall retained one of the guesthouses until her death. Dorothy Clune Murray leased the main house in 1946 and began renovating it. The city government added a temporary art-gallery wing in the 1950s; the wing was closed in 1967 and demolished soon afterward. Further renovations to the main house took place in the 1970s and the early 21st century.

The exterior walls are made of hollow clay tiles, wood frames, and stucco, sloping inward at their tops. The house is accessed by a long loggia and is surrounded by various terraces, with pools to its east and west. The house has 6,000 square feet (560 m²), spread across the living and music room wing to the west, the dining and kitchen wing to the north, and the gallery and bedroom wing to the south. The outbuildings are constructed of similar materials to the main house. The Barnsdall Art Park Foundation and the Friends of Hollyhock House help manage the house and its activities. Over the years, Hollyhock House has received extensive architectural commentary. It is designated as a National Historic Landmark. Hollyhock House is one of eight structures designated as part of "The 20th-Century Architecture of Frank Lloyd Wright", the first World Heritage Site in Los Angeles.

Hollyhock House is located on the northern slope of Olive Hill, a knoll within Barnsdall Art Park in the East Hollywood neighborhood of Los Angeles, California, United States. The house is at 4800 Hollywood Boulevard, between Vermont Avenue to the east and Edgemont Street to the west. The hill rises 490 feet (150 m) above sea level and 100 feet (30 m) above the street. The designs of several other buildings in the park, including a gallery, theater, and junior arts center, are inspired by that of Hollyhock House. Other structures, including apartments, stores, and a hospital, have been built around the house on three sides. The Vermont/Sunset station, served by Los Angeles Metro Rail's B Line, is southeast of the house.

Hollyhock House and Barnsdall Art Park were part of the estate of the heiress Aline Barnsdall, which measured 1,231 feet (375 m) wide from north to south and 1,255 feet (383 m) wide from west to east. The site was part of Rancho Los Feliz, a Spanish-era land grant given to José Vicente Feliz in 1802; the house's site was then acquired by James Lick in 1873 and subsequently subdivided. Before Barnsdall had acquired Olive Hill in 1919, there were low-rise stores and bungalows to the north. The hill itself was undeveloped and had contained olive trees since the 1890s, when J. H. Spires had developed an olive grove there. Despite being close to streetcar routes, Olive Hill was not appealing to developers because it was not near either Downtown Los Angeles or central Hollywood. The hill had hosted Easter services for years before Barnsdall's acquisition of the site, and it was used for the shooting of the 1916 film Intolerance. At the time of Barnsdall's purchase, the olive trees were planted 20 feet (6 m) apart on a grid. The hill was accessed by two roads from the southeast and northeast.

Hollyhock House's developer, Aline Barnsdall, was an oil heiress from Pennsylvania who had wanted to develop an arts and live-theater complex. In the early 1910s, Barnsdall traveled to Chicago to become a theatrical producer. She first met Wright in Chicago no later than early 1915, when she hired him to design a building for the Chicago Little Theatre. After vacationing in California, she decided to erect the theatrical building there instead; she wrote in early 1916 that she was searching for a site. Barnsdall originally wanted to build the theater in San Francisco, but she had changed her plans once more by early 1918, when she decided to construct a theatrical complex in Southern California. Barnsdall decided to hire Wright, with whom she had been in sporadic contact. In 1917, Barnsdall's father died and left her a large bequest, and Barnsdall also began planning a house for herself and her newborn daughter Betty.

Wright began drawing up conceptual plans for the house and theater in 1916, working on them at his Wisconsin studio, Taliesin. By early 1918, his plans called for a cube-shaped building with a circular auditorium containing 1,500 seats on two levels. This plan, a modification of his original plan for the Chicago Little Theatre, was similar to one designed by Norman Bel Geddes, who had been Barnsdall's stage designer. The house was to be designed in the Prairie style, with rooms surrounding an interior courtyard. By late 1918, Wright was preparing to go to Japan, where he was designing Tokyo's Imperial Hotel. At that time, Barnsdall was looking at potential sites in Los Angeles for her house and theater. Barnsdall had identified a potential site, the 36-acre (15 ha) Olive Hill tract, by mid-1919. However, the Olive Hill site may have been discussed even before that point, and Wright later told his son Lloyd that it was he who suggested that Barnsdall acquire Olive Hill. In any case, Wright's office still did not have the preliminary sketches for Barnsdall's house, and Wright's assistant Rudolph Schindler asked Barnsdall for the sketches.

On June 3, 1919, Barnsdall paid Mary Spires $300,000 for Olive Hill; the tract had been for sale for several years. The site was bounded by Hollywood Boulevard to the north, Edgemont Street to the west, Sunset Boulevard to the south, and Vermont Avenue to the east. News media reported that Wright had been hired to design a 1,200-seat theater for more than $200,000, which would face east toward Vermont Avenue. The theater would have had Greek-style motifs. Barnsdall donated part of the site, at Sunset Boulevard and Vermont Avenue, to the Community Theatre of Hollywood. She also planned a 17-room house, which was variously described as a Spanish-style structure and a "modernized Aztec" style. Barnsdall also told local media that she wanted to build houses, cottages, and apartment blocks on the site. Barnsdall was supposed to have gone to Japan to discuss the theater with Wright that August, but it is unknown whether Barnsdall actually made the trip. Instead, she asked the firm of Walker & Eisen to draw up alternate plans for the residence. Walker & Eisen proposed a five-bedroom Spanish Colonial structure costing $300,000, but Barnsdall decided not to accept these plans.