diff --git a/CHANGES.txt b/CHANGES.txt
index 97f7be243..acc087a9e 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -200,6 +200,8 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
       attribute and to explain what's being done in the example.
     - Test framework reformatted using settings from pyproject.toml.
       Includes code embedded in docstrings.
+    - Handle case of "memoizer" as one member of a comma-separated
+      --debug string - this was previously missed.
 
     From Adam Scott:
     - Changed Ninja's TEMPLATE rule pool to use `install_pool` instead of
diff --git a/RELEASE.txt b/RELEASE.txt
index 1b823b91d..54b4800a6 100644
--- a/RELEASE.txt
+++ b/RELEASE.txt
@@ -179,6 +179,9 @@ FIXES
 - Fix Issue #2281, AddPreAction() & AddPostAction() were being ignored if no action
   was specified when the Alias was initially created.
 
+- Handle case of "memoizer" as one member of a comma-separated
+  --debug string - this was previously missed.
+
 IMPROVEMENTS
 ------------
 
diff --git a/SCons/Script/__init__.py b/SCons/Script/__init__.py
index 2083e4f67..0243a9cf6 100644
--- a/SCons/Script/__init__.py
+++ b/SCons/Script/__init__.py
@@ -35,6 +35,7 @@
 start_time = time.time()
 
 import collections
+import itertools
 import os
 from io import StringIO
 
@@ -53,9 +54,17 @@
 # to not add the shims.  So we use a special-case, up-front check for
 # the "--debug=memoizer" flag and enable Memoizer before we import any
 # of the other modules that use it.
-
-_args = sys.argv + os.environ.get('SCONSFLAGS', '').split()
-if "--debug=memoizer" in _args:
+# Update: this breaks if the option isn't exactly "--debug=memoizer",
+# like if there is more than one debug option as a csv. Do a bit more work.
+
+_args = sys.argv + os.environ.get("SCONSFLAGS", "").split()
+_args = (
+    arg[len("--debug=") :].split(",")
+    for arg in _args
+    if arg.startswith("--debug=")
+)
+_args = list(itertools.chain.from_iterable(_args))
+if "memoizer" in _args:
     import SCons.Memoize
     import SCons.Warnings
     try:
diff --git a/test/option/debug-memoizer.py b/test/option/debug-memoizer.py
index 01af561b6..2425eaa0c 100644
--- a/test/option/debug-memoizer.py
+++ b/test/option/debug-memoizer.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,26 +22,21 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
-"""
-Test calling the --debug=memoizer option.
-"""
+"""Test calling the --debug=memoizer option."""
 
 import os
 
 import TestSCons
 
-test = TestSCons.TestSCons(match = TestSCons.match_re_dotall)
-
+test = TestSCons.TestSCons(match=TestSCons.match_re_dotall)
 
 test.write('SConstruct', """
-DefaultEnvironment(tools=[])
 def cat(target, source, env):
     with open(str(target[0]), 'wb') as f, open(str(source[0]), 'rb') as infp:
         f.write(infp.read())
+
+DefaultEnvironment(tools=[])
 env = Environment(tools=[], BUILDERS={'Cat':Builder(action=Action(cat))})
 env.Cat('file.out', 'file.in')
 """)
@@ -51,36 +48,35 @@ def cat(target, source, env):
 # names in the implementation, so if we change them, we'll have to
 # change this test...
 expect = [
-    "Memoizer (memory cache) hits and misses",
-    "Base.stat()",
+    # "Memoizer (memory cache) hits and misses",
     "Dir.srcdir_list()",
+    "File.stat()",
     "File.exists()",
     "Node._children_get()",
 ]
 
-
-for args in ['-h --debug=memoizer', '--debug=memoizer']:
-    test.run(arguments = args)
-    test.must_contain_any_line(test.stdout(), expect)
-
+test.run(arguments='--debug=memoizer')
+test.must_contain_any_line(test.stdout(), expect)
 test.must_match('file.out', "file.in\n")
-
-
-
 test.unlink("file.out")
 
+# make sure it also works if memoizer is not the only debug flag
+test.run(arguments='--debug=sconscript,memoizer')
+test.must_contain_any_line(test.stdout(), expect)
+test.must_match('file.out', "file.in\n")
+test.unlink("file.out")
 
+# memoization should still report even in help mode
+test.run(arguments='-h --debug=memoizer')
+test.must_contain_any_line(test.stdout(), expect)
+test.must_not_exist("file.out")
 
+# also try setting in SCONSFLAGS
 os.environ['SCONSFLAGS'] = '--debug=memoizer'
-
-test.run(arguments = '')
-
+test.run(arguments='.')
 test.must_contain_any_line(test.stdout(), expect)
-
 test.must_match('file.out', "file.in\n")
 
-
-
 test.pass_test()
 
 # Local Variables: