The increasing cost of soybean meal (SBM) has created an urgent need for economically viable alternative protein sources that maintain equivalent nutritional efficiency in ruminant diets. So this study aimed to provide cost-effective feed alternatives to expensive soybean meal by replacing it with cheaper materials while maintaining the same nutritional efficiency. The experiment was conducted at the Animal House, College of Veterinary Medicine, Tikrit University. Eighteen male Awassi lambs (3-4 months old, 20-26 kg initial weight) were randomly divided to three dietary treatments: T1, containing 8% soybean meal (SBM); T2, sesame meal replacement at 13% inclusion (SSM); and T3, sunflower meal replacement at 8% inclusion (SFM).. Rumen fluid samples were collected before feeding and 4 hours post-feeding to evaluate fermentation parameters, including pH, volatile fatty acids (VFAs), and ammonia nitrogen (NH3-N). Results demonstrated that both alternative protein sources significantly enhanced rumen fermentation activity compared to the control group. Post-feeding measurements revealed that the sesame and sunflower meal groups achieved higher VFA concentrations (67.14 and 67.46 mg/100 mL, respectively) compared to soybean meal (63.94 mg/100 mL). Similarly, ammonia nitrogen levels were significantly elevated in the alternative protein groups (25.11 and 25.17 mg/100 mL) versus the control (23.87 mg/100 mL). The pH values remained within optimal ranges across all treatments, indicating healthy rumen function. These findings suggest that sesame meal and sunflower meal can effectively replace soybean meal in growing lamb diets, offering economically advantageous alternatives without compromising rumen fermentation efficiency or nutritional performance.