diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index 40cc83a5fc5..6d5c5a48428 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -233,9 +233,9 @@ def check_blocksize_name(self, name, block_size=0, digest_size=0):
             self.assertEqual(m.block_size, block_size)
             self.assertEqual(m.digest_size, digest_size)
             self.assertEqual(len(m.digest()), digest_size)
-            self.assertEqual(m.name.lower(), name.lower())
+            self.assertEqual(m.name, name)
             # split for sha3_512 / _sha3.sha3 object
-            self.assertIn(name.split("_")[0], repr(m).lower())
+            self.assertIn(name.split("_")[0], repr(m))
 
     def test_blocksize_name(self):
         self.check_blocksize_name('md5', 64, 16)
diff --git a/Misc/NEWS b/Misc/NEWS
index df728eaaa3c..229a25900b4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -28,6 +28,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #18532: Change the builtin hash algorithms' names to lower case names
+  as promised by hashlib's documentation.
+
 - Issue #18405: Improve the entropy of crypt.mksalt().
 
 - Issue #12015: The tempfile module now uses a suffix of 8 random characters
diff --git a/Modules/md5module.c b/Modules/md5module.c
index 7dc38eaeedd..bb91b6c3698 100644
--- a/Modules/md5module.c
+++ b/Modules/md5module.c
@@ -439,7 +439,7 @@ MD5_get_block_size(PyObject *self, void *closure)
 static PyObject *
 MD5_get_name(PyObject *self, void *closure)
 {
-    return PyUnicode_FromStringAndSize("MD5", 3);
+    return PyUnicode_FromStringAndSize("md5", 3);
 }
 
 static PyObject *
diff --git a/Modules/sha1module.c b/Modules/sha1module.c
index e7c7ea671c4..403194c06be 100644
--- a/Modules/sha1module.c
+++ b/Modules/sha1module.c
@@ -411,7 +411,7 @@ SHA1_get_block_size(PyObject *self, void *closure)
 static PyObject *
 SHA1_get_name(PyObject *self, void *closure)
 {
-    return PyUnicode_FromStringAndSize("SHA1", 4);
+    return PyUnicode_FromStringAndSize("sha1", 4);
 }
 
 static PyObject *
diff --git a/Modules/sha256module.c b/Modules/sha256module.c
index 767bfac602f..e60111ad02d 100644
--- a/Modules/sha256module.c
+++ b/Modules/sha256module.c
@@ -501,9 +501,9 @@ static PyObject *
 SHA256_get_name(PyObject *self, void *closure)
 {
     if (((SHAobject *)self)->digestsize == 32)
-        return PyUnicode_FromStringAndSize("SHA256", 6);
+        return PyUnicode_FromStringAndSize("sha256", 6);
     else
-        return PyUnicode_FromStringAndSize("SHA224", 6);
+        return PyUnicode_FromStringAndSize("sha224", 6);
 }
 
 static PyGetSetDef SHA_getseters[] = {
diff --git a/Modules/sha512module.c b/Modules/sha512module.c
index 66c2c49c7f3..2841eabb2bf 100644
--- a/Modules/sha512module.c
+++ b/Modules/sha512module.c
@@ -567,9 +567,9 @@ static PyObject *
 SHA512_get_name(PyObject *self, void *closure)
 {
     if (((SHAobject *)self)->digestsize == 64)
-        return PyUnicode_FromStringAndSize("SHA512", 6);
+        return PyUnicode_FromStringAndSize("sha512", 6);
     else
-        return PyUnicode_FromStringAndSize("SHA384", 6);
+        return PyUnicode_FromStringAndSize("sha384", 6);
 }
 
 static PyGetSetDef SHA_getseters[] = {