diff --git a/reframe/frontend/loader.py b/reframe/frontend/loader.py
index 734e69b4b2..39a4d48dde 100644
--- a/reframe/frontend/loader.py
+++ b/reframe/frontend/loader.py
@@ -177,17 +177,23 @@ def load_from_module(self, module):
             if not self._validate_check(c):
                 continue
 
-            testfile = module.__file__
+            # Get the original filename in case of a different module name
+            if module.__name__ == c.__module__:
+                testfile = module.__file__
+            else:
+                testfile = inspect.getfile(c.__class__)
+
             try:
                 conflicted = self._loaded[c.unique_name]
             except KeyError:
                 self._loaded[c.unique_name] = testfile
                 final_tests.append(c)
             else:
-                raise NameConflictError(
-                    f'test {c.unique_name!r} from {testfile!r} '
-                    f'is already defined in {conflicted!r}'
-                )
+                if not c.is_fixture():
+                    raise NameConflictError(
+                        f'test {c.unique_name!r} from {testfile!r} '
+                        f'is already defined in {conflicted!r}'
+                    )
 
         getlogger().debug(f'  > Loaded {len(final_tests)} test(s)')
         return final_tests
diff --git a/unittests/resources/checks_unlisted/testlib_inheritance_bar.py b/unittests/resources/checks_unlisted/testlib_inheritance_bar.py
new file mode 100644
index 0000000000..874587335c
--- /dev/null
+++ b/unittests/resources/checks_unlisted/testlib_inheritance_bar.py
@@ -0,0 +1,13 @@
+# Copyright 2016-2023 Swiss National Supercomputing Centre (CSCS/ETH Zurich)
+# ReFrame Project Developers. See the top-level LICENSE file for details.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import reframe as rfm
+
+from testlib.simple import simple_echo_check
+
+
+@rfm.simple_test
+class HelloBar(simple_echo_check):
+    message = 'Bar'
diff --git a/unittests/resources/checks_unlisted/testlib_inheritance_foo.py b/unittests/resources/checks_unlisted/testlib_inheritance_foo.py
new file mode 100644
index 0000000000..9efd1b281f
--- /dev/null
+++ b/unittests/resources/checks_unlisted/testlib_inheritance_foo.py
@@ -0,0 +1,13 @@
+# Copyright 2016-2023 Swiss National Supercomputing Centre (CSCS/ETH Zurich)
+# ReFrame Project Developers. See the top-level LICENSE file for details.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import reframe as rfm
+
+from testlib.simple import simple_echo_check
+
+
+@rfm.simple_test
+class HelloFoo(simple_echo_check):
+    message = 'Foo'
diff --git a/unittests/resources/testlib/simple.py b/unittests/resources/testlib/simple.py
new file mode 100644
index 0000000000..a8be65e55f
--- /dev/null
+++ b/unittests/resources/testlib/simple.py
@@ -0,0 +1,31 @@
+# Copyright 2016-2023 Swiss National Supercomputing Centre (CSCS/ETH Zurich)
+# ReFrame Project Developers. See the top-level LICENSE file for details.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import reframe as rfm
+import reframe.utility.sanity as sn
+
+
+class dummy_fixture(rfm.RunOnlyRegressionTest, pin_prefix=True):
+    executable = 'echo'
+    sanity_patterns = sn.assert_true(1)
+
+
+@rfm.simple_test
+class simple_echo_check(rfm.RunOnlyRegressionTest):
+    descr = 'Simple Echo Test'
+    valid_systems = ['*']
+    valid_prog_environs = ['builtin']
+    executable = 'echo'
+    executable_opts = ['Hello']
+    message = variable(str, value='World') 
+    dummy = fixture(dummy_fixture, scope='environment')
+
+    @run_before('run')
+    def set_executable_opts(self):
+        self.executable_opts += [self.message]
+
+    @sanity_function
+    def assert_sanity(self):
+        return sn.assert_found(rf'Hello {self.message}', self.stdout)
diff --git a/unittests/test_cli.py b/unittests/test_cli.py
index 4cf8609204..bfdb59f366 100644
--- a/unittests/test_cli.py
+++ b/unittests/test_cli.py
@@ -1045,3 +1045,17 @@ def test_dynamic_tests_filtering(run_reframe, tmp_path):
     assert returncode == 0
     assert 'Ran 7/7 test case(s)' in stdout
     assert 'FAILED' not in stdout
+
+
+def test_testlib_inherit_fixture_in_different_files(run_reframe, monkeypatch):
+    monkeypatch.syspath_prepend('unittests/resources')
+    returncode, stdout, _ = run_reframe(
+        checkpath=[
+            'unittests/resources/checks_unlisted/testlib_inheritance_foo.py',
+            'unittests/resources/checks_unlisted/testlib_inheritance_bar.py'
+        ],
+        action='run',
+    )
+    assert returncode == 0
+    assert 'Ran 3/3 test case(s)' in stdout
+    assert 'FAILED' not in stdout