Abstract <p>Pistachio (<i>Pistacia vera</i> L.) is a product that has a high economic value. A resinous substance called “pistachio gum” is secreted in the trunk of the pistachio tree, mostly naturally and sometimes due to injury to the trunk bark. Pistachio gum has been used for different purposes in the many parts of the world. This study aimed to determine the anti-quorum sensing, antibacterial, and antioxidant potentials and total phenolic and flavonoid contents of pistachio gum. The antioxidant activity was determined by DPPH, ABTS, and FRAP methods and anti-quorum sensing activity was detected using the violacein inhibition method. To determine the antibacterial activity of pistachio gum, minimum inhibitory concentration (MIC) and maximum tolerable concentration (MTC) analyses were performed. Additionally, total phenolic and flavonoid contents were also analysed. As a result of the analyses, it was determined that pistachio gum has moderate antioxidant activity. While the total phenolic content of pistachio gum was determined as 17.2 mgGAE/g, the total flavonoid content was determined as 4.4 mgQE/g. Anti-quorum sensing activity was detected at varying rates in different amounts of substances. Moreover, <i>Pseudomonas aeruginosa</i> ATCC 9027 was determined as the most sensitive bacterium among test bacteria. Demonstrating that pistachio gum has anti-quorum sensing, antibacterial, and antioxidant activity is essential for evaluating its potential for use in different areas.</p>