The purpose of the publication is to define the specific characteristics of the functioning and role of the theater orchestra in the formation of symphonic performance in Kharkiv. The methodology. In the process of understanding the phenomenon of the Kharkiv Theater orchestra, a historical approach was applied, which allowed for the chronological reconstruction of the musical ensemble’s functioning. Additionally, a comparative analysis method was used to identify the unique features of the orchestra’s instrumental composition, repertoire development, and performance practices. The results. The specific functioning of theatrical instrumental ensembles in Kharkiv, which provided musical accompaniment for performances from the 1770s to the early 1870s, was examined. The study identifies factors that led to the establishment of a permanent “Orchestra of the Kharkiv Theater and Commercial Club”, which, besides performing in the theater, also served city artistic events from the mid 1840s to the 1870s. Key factors include the return of the Kharkiv Theater to private management in 1867, the activities of K. Vilboa from 1869 to 1873 aimed at creating a concert instrumental ensemble in the city, and the emergence of a new orchestra under the direction of G. Grazia in the Kharkiv Drama Theater in 1872. These developments facilitated the organization of symphonic concerts under the aegis of the Kharkiv branch of the Russian Musical Society from 1871. The scientific novelty lies in the determination that the primary source of symphonic performance in Kharkiv was the permanent orchestra of the Kharkiv Theater, active since the mid XIX century, whose instrumental and numerical composition met the demands of the provincial musical practices of that time. The conducting activities of K. Vilboa in Kharkiv during the late 1860s and the early 1870s were a driving force behind the formation of two orchestral ensembles in the city — the theater and club orchestras — whose instrumental and qualitative compositions aligned with the principles of symphonic performance. From 1871, in preparation for symphonic concerts by the Kharkiv branch of the Russian Musical Society, the theater and club orchestras were combined, each consisting of 20–30 musicians, ensuring that the symphonic orchestra met the required academic standards in terms of instrumental and numerical composition. Future research prospects are associated with identifying the specifics of symphonic performance in the cultural centers of Ukraine from the second half of the XIX century to the early XX century.