diff --git a/requirements.txt b/requirements.txt
index 9b455dd..2c6e2c7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,7 +21,7 @@ numpy==1.16.3
 palettable==3.1.1
 pandas==0.24.2
 phonopy==2.1.3
-Pillow==6.2.0
+Pillow==9.0.1
 pycparser==2.19
 PyDispatcher==2.0.5
 pymatgen==2019.4.11
diff --git a/setup.py b/setup.py
index bbfea9e..99feef5 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@
             'lxml~=4.3.3',
             'numpy~=1.16.3',
             'phonopy==2.1.3',
-            'Pillow~=6.2.0',
+            'Pillow>=6.2,<9.1',
             'pymatgen==2019.4.11',
             'ruamel.yaml~=0.15.94',
             'scipy~=1.2.1',