diff --git a/Cargo.lock b/Cargo.lock
index fa5e7b52236..3b7364c5327 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3548,6 +3548,7 @@ dependencies = [
  "optional",
  "rustpython-unicode",
  "rustpython-wtf8",
+ "unic-ucd-category",
 ]
 
 [[package]]
diff --git a/crates/sre_engine/src/string.rs b/crates/sre_engine/src/string.rs
index 5cc1b04b9fc..4d71be5ef4e 100644
--- a/crates/sre_engine/src/string.rs
+++ b/crates/sre_engine/src/string.rs
@@ -448,7 +448,6 @@ pub(crate) const fn is_uni_linebreak(ch: u32) -> bool {
 
 #[inline]
 pub(crate) fn is_uni_alnum(ch: u32) -> bool {
-    // TODO: check with cpython
     char::try_from(ch).is_ok_and(rustpython_unicode::classify::is_alnum)
 }
 
diff --git a/extra_tests/snippets/builtin_str.py b/extra_tests/snippets/builtin_str.py
index 684bd66a1ff..611f89c95a5 100644
--- a/extra_tests/snippets/builtin_str.py
+++ b/extra_tests/snippets/builtin_str.py
@@ -902,6 +902,15 @@ class MyString(str):
 assert id(b) != id(b * 2)
 
 
+# Regression tests for isalpha/isalnum Unicode General Category correctness.
+# These characters are in letter categories (Ll/Lo) and should return True,
+# but were missed in older Unicode tables used by unic-ucd-category.
+# See: https://github.com/RustPython/RustPython/pull/7520#issuecomment-4148322294
+for _cp in [1376, 1416, 1519, 2160, 2161, 2162, 2163, 2164, 2165, 2166]:
+    _c = chr(_cp)
+    assert _c.isalpha(), f"U+{_cp:04X} should be isalpha"
+    assert _c.isalnum(), f"U+{_cp:04X} should be isalnum"
+
 def test_huge_width():
     # A width that cannot be allocated is a MemoryError, not an aborted
     # process, and a tabsize wider than a C int does not fit at all.
diff --git a/extra_tests/snippets/builtin_str_unicode.py b/extra_tests/snippets/builtin_str_unicode.py
index ae2701d05ea..c83ff853523 100644
--- a/extra_tests/snippets/builtin_str_unicode.py
+++ b/extra_tests/snippets/builtin_str_unicode.py
@@ -11,6 +11,7 @@
 
 assert c == "👋👋👋"
 
+import re
 import unicodedata
 
 assert unicodedata.category("a") == "Ll"
@@ -44,3 +45,10 @@
 
 assert unicodedata.ucd_3_2_0.east_asian_width("\u231a") == "N"
 assert not unicodedata.ucd_3_2_0.mirrored("\u0f3a")
+
+# U+0345 COMBINING GREEK YPOGEGRAMMENI (category Mn) should not be alphanumeric.
+# CPython's isalpha/isalnum use Unicode letter categories (Lu/Ll/Lt/Lm/Lo),
+# not the broader Unicode Alphabetic derived property.
+assert not "\u0345".isalpha(), "isalpha should not match Mn category characters"
+assert not "\u0345".isalnum(), "isalnum should not match Mn category characters"
+assert not re.match(r"\w", "\u0345"), r"\w should not match U+0345 (category Mn)"