diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index aad0c62b21d..c8bbcb27bcb 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -428,6 +428,7 @@ def main(tests=None, testdir=None, verbose=0, quiet=False,
         elif o in ('-r', '--randomize'):
             randomize = True
         elif o == '--randseed':
+            randomize = True
             random_seed = int(a)
         elif o in ('-f', '--fromfile'):
             fromfile = a
diff --git a/Misc/NEWS b/Misc/NEWS
index f3a099dc506..564590ca72c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -468,6 +468,9 @@ Library
 Tests
 -----
 
+- Issue #18375: Assume --randomize when --randseed is used for running the
+  testsuite.
+
 - Issue #11185: Fix test_wait4 under AIX.  Patch by Sébastien Sablé.
 
 - Issue #18207: Fix test_ssl for some versions of OpenSSL that ignore seconds