diff --git a/java/ql/src/utils/modelconverter/ConvertExtensions.py b/java/ql/src/utils/modelconverter/ConvertExtensions.py
new file mode 100644
index 00000000000..c2d2e7b2e09
--- /dev/null
+++ b/java/ql/src/utils/modelconverter/ConvertExtensions.py
@@ -0,0 +1,41 @@
+# Tool to generate data extensions files based on the existing models.
+# Usage:
+# python3 ConvertExtensions.py
+# (1) A folder named `java/ql/lib/ext` will be created, if it doesn't already exist.
+# (2) The converted models will be written to `java/ql/lib/ext`. One file for each namespace.
+
+import os
+import subprocess
+import sys
+import tempfile
+
+# Add Models as Data script directory to sys.path.
+gitroot = subprocess.check_output(["git", "rev-parse", "--show-toplevel"]).decode("utf-8").strip()
+madpath = os.path.join(gitroot, "misc/scripts/models-as-data/")
+sys.path.append(madpath)
+
+import helpers
+import convert_extensions as extensions
+
+print('Running script to generate data extensions files from the existing MaD models.')
+print('Making a dummy database.')
+
+# Configuration
+language = "java"
+workDir = tempfile.mkdtemp()
+projectDir = os.path.join(workDir, "project")
+emptyFile = os.path.join(workDir, "Empty.java") 
+dbDir = os.path.join(workDir, "db")
+
+# Make dummy project
+with open(emptyFile, "w") as f:
+    f.write("class Empty {}")
+helpers.run_cmd(['codeql', 'database', 'create', f'--language={language}', '-c', f'javac {emptyFile}', dbDir], "Failed to create dummy database.")
+
+print('Converting data extensions for Java.')
+extensions.Converter(language, dbDir).run()
+
+print('Cleanup.')
+# Cleanup - delete database.
+helpers.remove_dir(dbDir)
+print('Done.')
\ No newline at end of file