diff --git a/requirements-dev.txt b/requirements-dev.txt
index a2f1896..18aaf3d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -13,7 +13,7 @@ identify==1.5.9
 idna==2.10
 importlib-metadata==2.0.0
 jsonpickle==1.4.1
-lxml==4.3.5
+lxml==4.9.1
 mock==4.0.2
 more-itertools==8.6.0; python_version > "2.7"
 nipyapi==0.15.0
diff --git a/requirements.txt b/requirements.txt
index 12afca8..29af29f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ docker==4.3.1
 idna==2.10
 importlib-metadata==2.0.0
 jsonpickle==1.4.1
-lxml==4.3.5
+lxml==4.9.1
 nipyapi==0.15.0
 packaging==20.4
 pygraphviz==1.6