diff --git a/.ci_support/environment-docs.yml b/.ci_support/environment-docs.yml
index 6e7d7895..912bb87a 100644
--- a/.ci_support/environment-docs.yml
+++ b/.ci_support/environment-docs.yml
@@ -11,7 +11,7 @@ dependencies:
 - numpy =1.26.3
 - scipy =1.14.1
 - spglib =2.5.0
-- phonopy =2.33.3
+- phonopy =2.33.4
 - structuretoolkit =0.0.28
 - seekpath =2.1.0
 - lammps =2024.06.27
diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 3c836f98..b32704ff 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -7,7 +7,7 @@ dependencies:
 - mendeleev =0.19.0
 - numpy =1.26.4
 - pandas =2.2.3
-- phonopy =2.33.3
+- phonopy =2.33.4
 - requests =2.32.3
 - scipy =1.14.1
 - seekpath =2.1.0
diff --git a/binder/environment.yml b/binder/environment.yml
index ad924db3..d104b086 100644
--- a/binder/environment.yml
+++ b/binder/environment.yml
@@ -5,7 +5,7 @@ dependencies:
 - numpy =1.26.4
 - scipy =1.14.1
 - spglib =2.5.0
-- phonopy =2.33.3
+- phonopy =2.33.4
 - structuretoolkit =0.0.28
 - seekpath =2.1.0
 - gpaw =24.6.0
diff --git a/pyproject.toml b/pyproject.toml
index 38472233..14796add 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,7 +38,7 @@ Repository = "https://github.com/pyiron/atomistics"
 
 [project.optional-dependencies]
 phonopy = [
-    "phonopy==2.33.3",
+    "phonopy==2.33.4",
     "seekpath==2.1.0",
     "structuretoolkit==0.0.28",
 ]