Background: The EORTC QLQ-C15-PAL is a shortened version of the widely used EORTC QLQ-C30. This questionnaire was developed to measure the symptoms and functional health of patients receiving palliative care. Objective: To enhance clinical interpretability of the EORTC QLQ-C15-PAL, our aim was to evaluate the sensitivity and specificity of thresholds for clinical importance developed previously for the QLQ-C30 when applied to the QLQ-C15-PAL scales. Design: Cross-sectional observational study. Setting/Subjects: Patients with cancer receiving any type of palliative treatment. Measurement: Patients completed the EORTC QLQ-C15-PAL and anchor items on limitations, worries, and need for help for each of the health domains covered by the questionnaire. The anchor items were summarized in a binary criterion for clinical importance to calculate the sensitivity and specificity of the thresholds for clinical importance. Results: In total, 225 patients participated in the study (mean age 64.5 years). Patients were recruited from Austria, Italy, the Netherlands, Poland, Spain, and the United Kingdom. The thresholds for clinical importance for the QLQ-C15-PAL scales showed a median sensitivity of 0.88 (range: 0.82 for sleep disturbances to 1.00 for dyspnea) and a median specificity of 0.74 (range: 0.54 for dyspnea to 0.89 for constipation). Conclusion: The thresholds for clinical importance showed high sensitivity and mostly high specificity in identifying clinically important symptoms and functional health impairments as assessed by the QLQ-C15-PAL. These thresholds will facilitate interpretation of EORTC QLQ-C15-PAL scores in daily clinical practice and clinical research.