diff --git a/Doc/library/re.rst b/Doc/library/re.rst
index 3f03f0341d81661..fd8eadec4589107 100644
--- a/Doc/library/re.rst
+++ b/Doc/library/re.rst
@@ -951,6 +951,8 @@ Functions
    .. versionchanged:: 3.7
       Non-empty matches can now start just after a previous empty match.
 
+   .. versionchanged:: 3.13
+      Negative start and end indices will no longer be truncated to zero in Python 3.15.
 
 .. function:: finditer(pattern, string, flags=0)
 
@@ -962,6 +964,8 @@ Functions
    .. versionchanged:: 3.7
       Non-empty matches can now start just after a previous empty match.
 
+   .. versionchanged:: 3.13
+      Negative start and end indices will no longer be truncated to zero in Python 3.15.
 
 .. function:: sub(pattern, repl, string, count=0, flags=0)
 
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index a6f5af17d7d51ba..154255cbd30cc1b 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -441,6 +441,18 @@ def test_bug_117612(self):
         self.assertEqual(re.findall(r"(a|(b))", "aba"),
                          [("a", ""),("b", "b"),("a", "")])
 
+    def test_bug_7940_raises_future_warnings(self):
+        """Test to ensure the FutureWarnings are raised."""
+        pat = re.compile(".")
+        with self.assertWarns(FutureWarning) as cm:
+            pat.findall("abcd", -1, 1)
+        self.assertEqual(str(cm.warning), "Negative start index will not "
+                "be truncated to zero in Python 3.15")
+        with self.assertWarns(FutureWarning) as cm:
+            pat.findall("abcd", 1, -1)
+        self.assertEqual(str(cm.warning), "Negative end index will not "
+                "be truncated to zero in Python 3.15")
+
     def test_re_match(self):
         for string in 'a', S('a'):
             self.assertEqual(re.match('a', string).groups(), ())
diff --git a/Misc/NEWS.d/next/Library/2023-07-23-11-57-33.gh-issue-52188.sXC663.rst b/Misc/NEWS.d/next/Library/2023-07-23-11-57-33.gh-issue-52188.sXC663.rst
new file mode 100644
index 000000000000000..f8e710b0028e337
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-07-23-11-57-33.gh-issue-52188.sXC663.rst
@@ -0,0 +1,2 @@
+Emit a FutureWarning when truncating negative start and end indices in re.finditer
+and re.findall.
diff --git a/Modules/_sre/sre.c b/Modules/_sre/sre.c
index ddbdc9f478aab3f..3d443ab4782b4cf 100644
--- a/Modules/_sre/sre.c
+++ b/Modules/_sre/sre.c
@@ -453,13 +453,22 @@ state_init(SRE_STATE* state, PatternObject* pattern, PyObject* string,
     }
 
     /* adjust boundaries */
-    if (start < 0)
+    if (start < 0) {
+        PyErr_WarnEx(PyExc_FutureWarning,
+                     "Negative start index will not be truncated to zero in Python 3.15",
+                     1);
         start = 0;
+    }
     else if (start > length)
         start = length;
 
-    if (end < 0)
+
+    if (end < 0) {
+        PyErr_WarnEx(PyExc_FutureWarning,
+                     "Negative end index will not be truncated to zero in Python 3.15",
+                     1);
         end = 0;
+    }
     else if (end > length)
         end = length;