The Bayreuth Festival (German: Bayreuther Festspiele) is a music festival held annually in Bayreuth, Germany, at which performances of stage works by the 19th-century German composer Richard Wagner are presented. Wagner himself conceived and promoted the idea of a special festival to showcase his own works, in particular his monumental cycle Der Ring des Nibelungen and Parsifal.

Performances take place in a specially designed theatre, the Bayreuth Festspielhaus. Wagner personally supervised the design and construction of the theatre, which contained many architectural innovations to accommodate the huge orchestras for which Wagner wrote as well as the composer's particular vision about the staging of his works. The Festival has become a pilgrimage destination for Wagnerians and classical-music enthusiasts.

The origins of the Festival itself lie rooted in Richard Wagner's interest in establishing his financial independence. A souring of the relationship with his patron, Ludwig II of Bavaria, led to his expulsion from Munich, where he had originally intended to launch the festival. Wagner next considered Nuremberg, which would have reinforced the thematic significance of works such as Die Meistersinger von Nürnberg. On the advice of Hans Richter, however, the focus fell upon Bayreuth which enjoyed three distinct advantages.

First, the town boasted a splendid venue: the Markgräfliches Opernhaus built for Margrave Frederick and his wife, Friederike Sophie Wilhelmine (sister of Frederick the Great) in 1747. With its ample capacity and strong acoustics, the opera house seemed a good match for Wagner's vision. Second, the town of Bayreuth was located outside those regions where Wagner no longer owned the rights to the performance of his own works, which he had sold off in 1864 in order to alleviate pressing financial concerns. Finally, the town had no cultural life that could offer competition to Wagner's own artistic dominance. The Festival, once launched, would be the dominant feature of Bayreuth's cultural landscape. In addition, "Richard Wagner did not want his works interpreted amid the hustle and noise or the distractions of a large city; he sought a place remote from the usual theatrical world where it was so quiet so that the hearers could concentrate their whole attention on the work offered, and could in the pauses refresh themselves in natural surroundings."

In April 1870, Wagner and his wife Cosima visited Bayreuth. On inspection, the opera house proved to be inadequate. It was built to accommodate the baroque orchestras of the 18th century and was therefore unsuited for the complex stagings and large orchestras that Wagner's later stage works required. Nonetheless, the burgermeisters proved open to assisting Wagner with the construction of an entirely new theatre, and the Festival was planned to launch in 1873. After a fruitless meeting in the spring of 1871 with the German Chancellor Otto von Bismarck to obtain funds, Wagner embarked on a fundraising tour across Germany, including Leipzig and Frankfurt.

An initial public subscription proved disappointing until Wagner, at the suggestion of his friend and admirer Emil Heckel, launched a number of Wagner Societies to increase participation in the Festival's subscription. Societies were established in Leipzig, Berlin, Vienna and other places.

Despite making direct appeals based on Wagner's role as a composer of the new German Reich, the Societies and other fundraising channels were well short of the needed sum by the end of 1872. Wagner made another appeal to Bismarck in August 1873 and was again denied.

Desperate, Wagner turned to his former patron, Ludwig II, who reluctantly agreed to help. In January 1874, Ludwig granted 100,000 Thaler and construction on the theatre, designed by architect Gottfried Semper, started shortly thereafter. Semper, inspired by the classical amphitheater, built a double proscenium in the theatre, creating a necessary space between the listener's "real world" and the imaginary world that occurred on stage. Later in the construction of the theatre, architect Carl Brandt expanded Semper's double proscenium to six pairs of proscenia, and also created its amphitheater shape. Performances featured a sunken pit and dimmed lighting; it is clear that Wagner was adamant about controlling the audience's visual and aural experience during his performances. These specific considerations resulted in a delayed opening of the theatre. A planned 1875 debut was postponed for a year due to construction and other delays.