To externally validate the prognostic impact of copeptin, either alone or integrated in risk stratification models, in pulmonary embolism (PE), we performed a post hoc analysis of 843 normotensive PE patients prospectively included in three European cohorts.Within the first 30 days, 21 patients (2.5%, 95% CI 1.5–3.8) had an adverse outcome and 12 (1.4%, 95% CI 0.7–2.5) died due to PE. Patients with copeptin ≥24 pmol·L⁻¹ had a 6.3-fold increased risk for an adverse outcome (95% CI 2.6–15.5, p<0.001) and a 7.6-fold increased risk for PE-related death (95% CI 2.3–25.6, p=0.001). Risk classification according to the 2014 European Society of Cardiology (ESC) guideline algorithm identified 248 intermediate-high-risk patients (29.4%) with 5.6% (95% CI 3.1–9.3) at risk of adverse outcomes. A stepwise biomarker-based risk assessment strategy (based on high-sensitivity troponin T, N-terminal pro-brain natriuretic peptide and copeptin) identified 123 intermediate-high-risk patients (14.6%) with 8.9% (95% CI 4.5–15.4) at risk of adverse outcomes. The identification of patients at higher risk was even better when copeptin was measured on top of the 2014 ESC algorithm in intermediate-high-risk patients (adverse outcome OR 11.1, 95% CI 4.6–27.1, p<0.001; and PE-related death OR 13.5, 95% CI 4.2–43.6, p<0.001; highest risk group versus all other risk groups). This identified 85 patients (10.1%) with 12.9% (95% CI 6.6–22.0) at risk of adverse outcomes and 8.2% (95% CI 3.4–16.2) at risk of PE-related deaths.Copeptin improves risk stratification of normotensive PE patients, especially when identifying patients with an increased risk of an adverse outcome.