This study aimed to evaluate the effects of natural extracts and Burkholderia spp. bacterial strains on the growth, yield, and quality of lettuce (Lactuca sativa cv. Muir) under greenhouse conditions. The experiment was conducted using a completely randomized block design with two factors: (A) two natural extracts (catfish waste extract FE and soybean oil cake extract SE), and (B) three bacterial strains (MP1, MP2, MP3), and no bacterial strain. A total of 8 treatments were set up, with 6 replications per treatment. Agronomic parameters were recorded at 15, 35, and 55 days after sowing (DAS) to evaluate the growth-promoting effects of the extracts and bacterial strains on Muir lettuce. The yield components and quality parameters were determined at 55 DAS. The results demonstrated that the FE extract was more effective than the SE extract (p<0.01), enhancing plant growth, producing marketable head weights of 300 g.plant^-1 and 287 g.plant^-1, respectively. Similarly, the MP1 strain significantly enhanced the growth and the marketable head weight. The application of natural extracts with bacterial strains reduced postharvest weight loss to below 5% after a 15-day storage period...