diff --git a/requirements.txt b/requirements.txt
index 0ef3fe4..88df00b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -42,7 +42,7 @@ jsonref==1.1.0
     #   ocdsextensionregistry
     #   ocdskit
     #   ocdsmerge
-lxml==4.9.3
+lxml==6.1.0
     # via flattentool
 numpy==1.24.4
     # via
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 9f3a076..d98e869 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -65,7 +65,7 @@ jsonref==1.1.0
     #   ocdsextensionregistry
     #   ocdskit
     #   ocdsmerge
-lxml==4.9.3
+lxml==6.1.0
     # via
     #   -r requirements.txt
     #   flattentool