diff --git a/docs/changelog/80.feature.rst b/docs/changelog/80.feature.rst
new file mode 100644
index 0000000..47e39a3
--- /dev/null
+++ b/docs/changelog/80.feature.rst
@@ -0,0 +1,2 @@
+Add ``debug_build`` attribute to :class:`PythonInfo` exposing whether the interpreter is a debug build
+(``Py_DEBUG``) - by :user:`gaborbernat`.
diff --git a/src/python_discovery/_py_info.py b/src/python_discovery/_py_info.py
index 2679ae4..5022b60 100644
--- a/src/python_discovery/_py_info.py
+++ b/src/python_discovery/_py_info.py
@@ -12,6 +12,7 @@
 import sysconfig
 import warnings
 from collections import OrderedDict
+from itertools import product
 from string import digits
 from typing import TYPE_CHECKING, ClassVar, Final, NamedTuple
 
@@ -73,6 +74,7 @@ def _init_identity(self) -> None:
         self.version = sys.version
         self.os = os.name
         self.free_threaded = sysconfig.get_config_var("Py_GIL_DISABLED") == 1
+        self.debug_build = bool(sysconfig.get_config_var("Py_DEBUG"))
 
     def _init_prefixes(self) -> None:
         def abs_path(value: str | None) -> str | None:
@@ -404,10 +406,11 @@ def machine(self) -> str:
     @property
     def spec(self) -> str:
         """A specification string identifying this interpreter (e.g. ``CPython3.13.2-64-arm64``)."""
-        return "{}{}{}-{}-{}".format(
+        return "{}{}{}{}-{}-{}".format(
             self.implementation,
             ".".join(str(i) for i in self.version_info),
             "t" if self.free_threaded else "",
+            "d" if self.debug_build else "",
             self.architecture,
             self.machine,
         )
@@ -731,17 +734,14 @@ def _find_possible_folders(self, inside_folder: str) -> list[str]:
 
     def _find_possible_exe_names(self) -> list[str]:
         name_candidate = OrderedDict()
+        mods = ["", "t"] if self.free_threaded else [""]
+        debug_suffixes = ["_d", ""] if self.debug_build else [""]
+        archs = [f"-{self.architecture}", ""]
         for name in self._possible_base():
             for at in (3, 2, 1, 0):
                 version = ".".join(str(i) for i in self.version_info[:at])
-                mods = [""]
-                if self.free_threaded:
-                    mods.append("t")
-                for mod in mods:
-                    for arch in [f"-{self.architecture}", ""]:
-                        for ext in EXTENSIONS:
-                            candidate = f"{name}{version}{mod}{arch}{ext}"
-                            name_candidate[candidate] = None
+                for mod, debug, arch, ext in product(mods, debug_suffixes, archs, EXTENSIONS):
+                    name_candidate[f"{name}{version}{mod}{debug}{arch}{ext}"] = None
         return list(name_candidate.keys())
 
     def _possible_base(self) -> Generator[str, None, None]:
diff --git a/tests/py_info/test_py_info.py b/tests/py_info/test_py_info.py
index 92c23d8..162a757 100644
--- a/tests/py_info/test_py_info.py
+++ b/tests/py_info/test_py_info.py
@@ -40,6 +40,7 @@ def test_current_as_json() -> None:
         "serial": serial,
     }
     assert parsed["free_threaded"] is free_threaded
+    assert parsed["debug_build"] is bool(sysconfig.get_config_var("Py_DEBUG"))
 
 
 def test_bad_exe_py_info_raise(tmp_path: Path, session_cache: DiskCache) -> None:
@@ -418,6 +419,28 @@ def test_py_info_satisfies_machine_cross_os_normalization(platform: str, spec_ma
     assert info.satisfies(spec, impl_must_match=True) is True
 
 
+@pytest.mark.parametrize("debug", [True, False], ids=["debug", "release"])
+def test_py_info_debug_build_in_spec(*, debug: bool) -> None:
+    info = copy.deepcopy(CURRENT)
+    info.debug_build = debug
+    assert ("d-" in info.spec) is debug
+
+
+@pytest.mark.parametrize("debug", [True, False], ids=["debug", "release"])
+def test_py_info_debug_build_exe_names(*, debug: bool) -> None:
+    info = copy.deepcopy(CURRENT)
+    info.debug_build = debug
+    names = info._find_possible_exe_names()
+    assert any("_d" in n for n in names) is debug
+
+
+def test_py_info_debug_build_json_round_trip() -> None:
+    info = copy.deepcopy(CURRENT)
+    info.debug_build = True
+    restored = PythonInfo.from_json(info.to_json())
+    assert restored.debug_build is True
+
+
 def test_py_info_to_dict_includes_sysconfig_platform() -> None:
     data = CURRENT.to_dict()
     assert "sysconfig_platform" in data