diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 7732ee154..a2ddb85c5 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -7,7 +7,7 @@ dependencies:
 - coverage
 - dscribe =2.1.2
 - matplotlib-base =3.10.8
-- nglview =3.1.4
+- nglview =4.0
 - notebook
 - numpy =2.3.5
 - phonopy =2.46.1
diff --git a/pyproject.toml b/pyproject.toml
index 197e17a5b..781eecfc8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -42,7 +42,7 @@ grainboundary = [
     "pymatgen==2025.10.7",
 ]
 pyscal = ["pyscal3==3.3.0"]
-nglview = ["nglview==3.1.4"]
+nglview = ["nglview==4.0"]
 matplotlib = ["matplotlib==3.10.8"]
 plotly = ["plotly==6.5.0"]
 clusters = ["scikit-learn==1.7.2"]