diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index aec0aa3..1f6745e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -35,7 +35,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", pypy-3.10]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13", pypy-3.10]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
diff --git a/pyproject.toml b/pyproject.toml
index aa47cdc..36ea8af 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -87,7 +87,7 @@ warn_unused_ignores = true
 [tool.tox]
 legacy_tox_ini = """
 [tox]
-envlist = py37, py38, py39, py310, py311, py312, pypy3
+envlist = py37, py38, py39, py310, py311, py312, py313, pypy3
 labels =
     typing = py{310,311,312}-typing
 skip_missing_interpreters = true
diff --git a/tests/test_formatting.py b/tests/test_formatting.py
index f6b9bc2..557fcc8 100644
--- a/tests/test_formatting.py
+++ b/tests/test_formatting.py
@@ -64,12 +64,15 @@ def test_exceptionhook(capsys: CaptureFixture) -> None:
     local_lineno = test_exceptionhook.__code__.co_firstlineno
     lineno = raise_excgroup.__code__.co_firstlineno
     module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
+    underline_suffix = (
+        "" if sys.version_info < (3, 13) else "\n  |     ~~~~~~~~~~~~~~^^"
+    )
     output = capsys.readouterr().err
     assert output == (
         f"""\
   + Exception Group Traceback (most recent call last):
   |   File "{__file__}", line {local_lineno + 2}, in test_exceptionhook
-  |     raise_excgroup()
+  |     raise_excgroup(){underline_suffix}
   |   File "{__file__}", line {lineno + 15}, in raise_excgroup
   |     raise exc
   | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
@@ -163,13 +166,16 @@ def test_exceptionhook_format_exception_only(capsys: CaptureFixture) -> None:
     local_lineno = test_exceptionhook_format_exception_only.__code__.co_firstlineno
     lineno = raise_excgroup.__code__.co_firstlineno
     module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
+    underline_suffix = (
+        "" if sys.version_info < (3, 13) else "\n  |     ~~~~~~~~~~~~~~^^"
+    )
     output = capsys.readouterr().err
     assert output == (
         f"""\
   + Exception Group Traceback (most recent call last):
   |   File "{__file__}", line {local_lineno + 2}, in \
 test_exceptionhook_format_exception_only
-  |     raise_excgroup()
+  |     raise_excgroup(){underline_suffix}
   |   File "{__file__}", line {lineno + 15}, in raise_excgroup
   |     raise exc
   | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
@@ -204,13 +210,14 @@ def test_formatting_syntax_error(capsys: CaptureFixture) -> None:
         underline = "\n     ^"
 
     lineno = test_formatting_syntax_error.__code__.co_firstlineno
+    underline_suffix = "" if sys.version_info < (3, 13) else "\n    ~~~~^^^^^^^^^^^^"
     output = capsys.readouterr().err
     assert output == (
         f"""\
 Traceback (most recent call last):
   File "{__file__}", line {lineno + 2}, \
 in test_formatting_syntax_error
-    exec("//serser")
+    exec("//serser"){underline_suffix}
   File "<string>", line 1
     //serser{underline}
 SyntaxError: invalid syntax
@@ -254,11 +261,14 @@ def test_format_exception(
         lineno = raise_excgroup.__code__.co_firstlineno
         assert isinstance(lines, list)
         module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
+        underline_suffix = (
+            "" if sys.version_info < (3, 13) else "\n  |     ~~~~~~~~~~~~~~^^"
+        )
         assert "".join(lines) == (
             f"""\
   + Exception Group Traceback (most recent call last):
   |   File "{__file__}", line {local_lineno + 25}, in test_format_exception
-  |     raise_excgroup()
+  |     raise_excgroup(){underline_suffix}
   |   File "{__file__}", line {lineno + 15}, in raise_excgroup
   |     raise exc
   | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
@@ -303,6 +313,10 @@ def raise_exc(max_level: int, level: int = 1) -> NoReturn:
     except Exception as exc:
         lines = format_exception(type(exc), exc, exc.__traceback__)
 
+    underline_suffix1 = (
+        "" if sys.version_info < (3, 13) else "\n    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^"
+    )
+    underline_suffix2 = "" if sys.version_info < (3, 13) else "\n    ~~~~~~~~~^^^"
     local_lineno = test_format_nested.__code__.co_firstlineno + 20
     raise_exc_lineno1 = raise_exc.__code__.co_firstlineno + 2
     raise_exc_lineno2 = raise_exc.__code__.co_firstlineno + 5
@@ -312,7 +326,7 @@ def raise_exc(max_level: int, level: int = 1) -> NoReturn:
         f"""\
 Traceback (most recent call last):
   File "{__file__}", line {raise_exc_lineno2}, in raise_exc
-    raise_exc(max_level, level + 1)
+    raise_exc(max_level, level + 1){underline_suffix1}
   File "{__file__}", line {raise_exc_lineno1}, in raise_exc
     raise Exception(f"LEVEL_{{level}}")
 Exception: LEVEL_3
@@ -321,7 +335,7 @@ def raise_exc(max_level: int, level: int = 1) -> NoReturn:
 
 Traceback (most recent call last):
   File "{__file__}", line {raise_exc_lineno2}, in raise_exc
-    raise_exc(max_level, level + 1)
+    raise_exc(max_level, level + 1){underline_suffix1}
   File "{__file__}", line {raise_exc_lineno3}, in raise_exc
     raise Exception(f"LEVEL_{{level}}")
 Exception: LEVEL_2
@@ -330,7 +344,7 @@ def raise_exc(max_level: int, level: int = 1) -> NoReturn:
 
 Traceback (most recent call last):
   File "{__file__}", line {local_lineno}, in test_format_nested
-    raise_exc(3)
+    raise_exc(3){underline_suffix2}
   File "{__file__}", line {raise_exc_lineno3}, in raise_exc
     raise Exception(f"LEVEL_{{level}}")
 Exception: LEVEL_1
@@ -388,12 +402,15 @@ def test_print_exception(
         local_lineno = test_print_exception.__code__.co_firstlineno
         lineno = raise_excgroup.__code__.co_firstlineno
         module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
+        underline_suffix = (
+            "" if sys.version_info < (3, 13) else "\n  |     ~~~~~~~~~~~~~~^^"
+        )
         output = capsys.readouterr().err
         assert output == (
             f"""\
   + Exception Group Traceback (most recent call last):
   |   File "{__file__}", line {local_lineno + 13}, in test_print_exception
-  |     raise_excgroup()
+  |     raise_excgroup(){underline_suffix}
   |   File "{__file__}", line {lineno + 15}, in raise_excgroup
   |     raise exc
   | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
@@ -433,12 +450,15 @@ def test_print_exc(
         local_lineno = test_print_exc.__code__.co_firstlineno
         lineno = raise_excgroup.__code__.co_firstlineno
         module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
+        underline_suffix = (
+            "" if sys.version_info < (3, 13) else "\n  |     ~~~~~~~~~~~~~~^^"
+        )
         output = capsys.readouterr().err
         assert output == (
             f"""\
   + Exception Group Traceback (most recent call last):
   |   File "{__file__}", line {local_lineno + 13}, in test_print_exc
-  |     raise_excgroup()
+  |     raise_excgroup(){underline_suffix}
   |   File "{__file__}", line {lineno + 15}, in raise_excgroup
   |     raise exc
   | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)