Crosby's Opera House (1865–1871) was an opera house in Chicago, Illinois, United States. It was founded by Uranus H. Crosby in 1865 with the goal of advancing the arts in Chicago by bringing opera to the city. The five-story building was designed by William W. Boyington and contained statues of painting, sculpture, music and commerce that welcomed visitors as they entered through the arch of the building. After holding only occasional performances, Crosby ran into many business difficulties that resulted in a decision to sell the building in 1866. The Crosby Opera House Art Association was formed to help Crosby sell the building by lottery. The lottery distributed over 210,000 tickets, awarding purchasers great works of art and even the building itself. After being sold back to Crosby by the lottery winner, A.H. Lee, the hall began producing more consistent performances. The opera house stood for less than six and a half years before it was destroyed in the Great Chicago Fire of 1871 and was never rebuilt.

In 1989 the city demolished the deteriorated properties on the site where it once stood, and took decades to subsequently formalize plans for redevelopment of the so-called Block 37. During the city's twenty-year discussion regarding what to do with the property, it was used as an art studio for Chicago public school students and as a skating rink through the winter season.

Uranus Harold Crosby came to Chicago from Chatham, Massachusetts, on September 4, 1850. He did so on recommendation of his cousin Albert, who insisted that the city was well-cultured. Albert had arrived two years earlier to establish a liquor and tea trading house, Albert Crosby & Co. In 1851, the cousins established a liquor manufactory and the operation became the largest wholesale distributor of distilled alcohol and camphine.

Despite his new-found wealth, Uranus Crosby was disappointed at the lack of culture that he was promised in Chicago. The growing city could offer little more than brothels, saloons, and gambling houses for entertainment. The area's only theater, built by John Blake Rice in 1847, had been destroyed in a fire shortly before Crosby's arrival. When Rice rebuilt the theater in 1851, Crosby was disappointed by Rice's lack of interest in exhibiting opera performances. James Hubert McVicker, a close friend of Crosby's who was a neighbor in the Briggs House hotel, built a playhouse. Crosby probably assisted McVicker with raising credit for the institution.

By 1855, Rice had retired from the theater business, leaving his theater a house of novelty shows. McVicker's Theater became the cultural center of Chicago entertainment, but Crosby believed that the city was overdue for a grand opera house like the ones he knew back East. He selected a site on the north side of Washington Street between State Street and Dearborn Avenue, then embarked with architect William W. Boyington on a tour of opera houses in Union cities. Boyington then designed Crosby's Opera House with assistant architect John W. Roberts.

The building itself was five stories. The first floor housed businesses like music publishers Root & Cady, the piano store of W.W. Kimball, and the restaurant of H.M. Kinsley. The second and third floors were occupied by business offices and the fourth floor was an art gallery equipped with studios for the artists. The 3,000-seat opera house was situated in the rear of the building. The center of the ceiling was a dome encircled by paintings of Beethoven, Mozart, Auber, Weber, Verdi, and Wagner. Surrounding it were frescoes that were painted by Otto Jevne and Peter M. Almini, who were partners in a Chicago decorating firm specializing in ornamental painting. A forty-foot painting of Aurora, based on Guido Reni's fresco, was displayed at the front of the stage above the orchestra. Wellbaum & Bauman handled carpentry and masonry with cut stone work by L. H. Boldenweck. The structure cost $600,000 (equivalent to $12,620,000 in 2025), which ruined Crosby financially.

Crosby's Opera House was scheduled to open April 17, 1865. The conductor Jules Grau would lead the inaugural series of Italian operas, performed by a company from New York City's Academy of Music featuring Clara Louise Kellogg. However, the assassination of Abraham Lincoln forced a three-day delay in the house's opening. Il trovatore was the first performance, followed by a four-week season with Lucia di Lammermoor, Il Poliuto, Martha, Norma, Faust, Linda di Chamounix, La sonnambula, I puritani, Un ballo in maschera, Dom Sébastien, Lucrezia Borgia, Ernani, and Fra Diavolo. Many of the performances were assessed by critic George Upton, a critic for the Chicago Tribune who arrived to Chicago in 1855 with a bachelor of music degree from Brown University. Upton favored Italian opera and had strong feelings against Wagnerian opera.

Because the opera house did not employ a permanent company, performances were not consistently scheduled. In late May 1865, three comedies and a performance of Hamlet were staged as a benefit for the Chicago Sanitary Fair. Karl Formes gave concerts that September, followed by performances by the Hanlon Brothers comedy group. The Music Hall annex, intended mostly for lectures and concerts, was completed on November 29. It was here that Edwin Forrest made his first appearance in Chicago since 1848 on January 22, 1866, with a company led by John Edward McCullough and James Edward Murdoch gave a reading for charity on February 5, 1866.