Aim: This study aims to elucidate both the anti-virulence and antimicrobial effects of ethanol extracts from Hypericum calycinum L. and Parietaria officinalis L. Material and Methods: Antimicrobial activity was evaluated using the well diffusion method against five bacteria and two yeast isolates involved in human urinary tract infections (UTIs). The potential of the extracts to inhibit quorum sensing (QS), was assessed using the biosensor strain Chromobacterium violaceum ATCC 12472. Additionally, the antibiofilm activities were investigated using a microplate biofilm assay on Escherichia coli and Pseudomonas aeruginosa. Results: H. calycinum exhibited the highest inhibitory effect at a concentration of 100 mg/mL against Candida albicans with an inhibition zone of 24.5±0.71 mm, while P. officinalis showed its highest effect at the same concentration against E. coli with an inhibition zone of 15.5±0.71 mm. Overall, H. calycinum demonstrated stronger antimicrobial activity compared to P. officinalis. Both plant extracts inhibited QS at similar levels, with inhibition zones ranging between 10-12 mm. The antibiofilm effect varied depending on the bacterial species, but notably, P. officinalis extract exhibited over 80% antibiofilm efficacy against E. coli at all concentrations. Conclusion: This study demonstrates that H. calycinum L. and P. officinalis L. are potent antimicrobial agents against UTI pathogens. While their anti-QS efficacy is not exceptional, the significant inhibition of E. coli biofilm formation underscores their potential as formidable agents. Designed as a fundamental study, it highlights the promising antimicrobial properties of these plant extracts and marks the first investigation into their capabilities as QS and biofilm-preventive agents.