diff --git a/setup.py b/setup.py
index 97a32fa56..e093e1f95 100644
--- a/setup.py
+++ b/setup.py
@@ -32,6 +32,9 @@ VERSION_PY_FILENAME = 'src/allmydata/_version.py'
 version = read_version_py(VERSION_PY_FILENAME)
 
 install_requires = [
+    # importlib.resources.files and friends are new in Python 3.9.
+    "importlib_resources; python_version < '3.9'",
+
     "zfec >= 1.1.0",
 
     # zope.interface >= 3.6.0 is required for Twisted >= 12.1.0.
diff --git a/src/allmydata/web/common.py b/src/allmydata/web/common.py
index 982be491a..93aba55f7 100644
--- a/src/allmydata/web/common.py
+++ b/src/allmydata/web/common.py
@@ -4,7 +4,12 @@ Ported to Python 3.
 from __future__ import annotations
 
 from six import ensure_str
-from importlib.resources import files as resource_files, as_file
+try:
+    from importlib.resources import files as resource_files, as_file
+except ImportError:
+    import sys
+    assert sys.version_info[:2] < (3, 9)
+    from importlib_resources import files as resource_files, as_file
 from contextlib import ExitStack
 import weakref
 from typing import Optional, Union, TypeVar, overload