Objectives/Hypothesis: Clinical trials of biologics to treat chronic rhinosinusitis with nasal polyposis (CRSwNP) have evaluated objective outcomes (e.g., University of Pennsylvania Smell Identification Test [UPSIT], nasal polyps score [NPS], and computed tomography Lund-Mackay score [CT-LMK]) and patient-reported symptoms (e.g., nasal congestion/obstruction [NC], loss of smell [LoS], and total symptom score [TSS]). We estimated anchor-based thresholds for clinically meaningful change in objective and patient-reported outcomes in patients with CRSwNP using data from LIBERTY NP SINUS-24 and SINUS-52 trials (NCT02912468; NCT02898454). Methods: Target patient-reported outcomes were NC, LoS, and TSS; target objective outcomes were UPSIT, NPS, and CT-LMK. Anchor measures were the 22-item sinonasal outcome test (SNOT-22) rhinologic symptoms domain and total score and rhinosinusitis visual analog scale (VAS). The appropriateness of each anchor measure was evaluated by reviewing correlations between change in anchor measures and target outcomes and descriptive scores on target outcomes by levels of change in the anchor measure. Established thresholds for anchor measures (3.8 points for SNOT-22 rhinologic symptoms, 8.9 points for SNOT-22 total, 1-category improvement for rhinosinusitis VAS) were used to estimate clinically meaningful score changes for each target outcome. Results: Based on correlations between change in anchor measures and target outcomes, SNOT-22 rhinologic symptoms domain was deemed the most appropriate anchor measure. Using this anchor measure, thresholds for clinically meaningful within-patient change were NC: 1 point; LoS: 1 point; TSS: 3 points; UPSIT: 8 points; NPS: 1 point; and CT-LMK: 5 points. Conclusion: These thresholds support interpretation of efficacy results for target outcomes in CRSwNP trials. Level of Evidence: 2 Laryngoscope, 132:265–271, 2022.