Objective: Investigating the concordance of prolonged grief disorder (PGD) criteria that have been recently introduced to the 5th text revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) and the International Classification of Diseases 11 th Revision (ICD-11). Method: N = 193 treatmentseeking bereaved adults were assessed with the prolonged grief disorder 13 + 9 interview. Data were examined in terms of (a) diagnostic rates for PGD DSM-5-TR and PGD ICD-11 , including increases of the PGD ICD-11 accessory symptom threshold (PGD ICD-11-X+ ) and time criterion (PGD ICD-11-12 months ), (b) dimensionality, (c) the frequency with which single PGD symptoms occur, and (d) concurrent validity in terms of psychological symptoms and loss-related characteristics. Results: The diagnostic rate of PGD DSM-5-TR (52%) was significantly lower than that of PGD ICD-11 (76%) and agreement between the two criteria sets was moderate, κ = 0.51, 95% CI [0.47-0.55]. Increasing the PGD ICD-11 accessory symptom threshold did not improve the diagnostic agreement. In contrast, increasing the ICD-11 time criterion led to almost perfect agreement between PGD ICD-11-12 months and PGD DSM-5-TR , κ = 0.91, 95% CI [0.89-0.93]. Confirmatory factor analysis results indicated a one-factor model fit best for both PGD DSM-5-TR and PGD ICD-11. Emotional pain symptoms (e.g., guilt) were predominantly reported by patients with a PGD ICD-11 diagnosis, while attachment disturbance symptoms (e.g., identity disruption) were reported more often by patients with a PGD DSM-5-TR diagnosis. Conclusions: Despite methodological limitations of this study, results indicate discordance in PGD DSM-5-TR and PGD ICD-11 regarding diagnostic rates and single symptom occurrence, while