diff --git a/tests/application/discovery/__init__.py b/tests/application/discovery/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/application/discovery/sample.py b/tests/application/discovery/sample.py
new file mode 100644
index 00000000..947a9b0f
--- /dev/null
+++ b/tests/application/discovery/sample.py
@@ -0,0 +1,5 @@
+from .sample_helpers import SampleHelper
+
+
+class Sample:
+    helper = SampleHelper
diff --git a/tests/application/discovery/sample_helpers.py b/tests/application/discovery/sample_helpers.py
new file mode 100644
index 00000000..da45ac6c
--- /dev/null
+++ b/tests/application/discovery/sample_helpers.py
@@ -0,0 +1,2 @@
+class SampleHelper:
+    pass
diff --git a/tests/application/test_module_discovery.py b/tests/application/test_module_discovery.py
index dfb48e0d..611accbf 100644
--- a/tests/application/test_module_discovery.py
+++ b/tests/application/test_module_discovery.py
@@ -30,3 +30,21 @@ def test_all_subclasses_with_exception(reference_type):
     reference_type.side_effect = TypeError
     exception_subclasses = list(get_all_subclasses(Exception))
     assert not exception_subclasses
+
+
+def test_get_all_classes_of_module():
+    from tests.application.discovery.sample import Sample
+
+    found_classes = list(get_all_classes('tests.application.discovery.sample'))
+
+    # SampleHelper is imported into the module but defined in a module whose name only starts the same
+    assert found_classes == [('Sample', Sample)]
+
+
+def test_get_all_classes_of_package():
+    from tests.application.discovery.sample import Sample
+    from tests.application.discovery.sample_helpers import SampleHelper
+
+    found_classes = list(get_all_classes('tests.application.discovery'))
+
+    assert sorted(found_classes) == [('Sample', Sample), ('SampleHelper', SampleHelper)]
diff --git a/tests/web/test_autodiscovery.py b/tests/web/test_autodiscovery.py
index 6ba0147f..43395824 100644
--- a/tests/web/test_autodiscovery.py
+++ b/tests/web/test_autodiscovery.py
@@ -7,3 +7,11 @@ def test_find_package_routes():
 
     # Assert
     assert [route.url_path for route in routes] == ['api_1/', 'api_2/', 'api_2/', 'api_3/']
+
+
+def test_find_module_routes():
+    # Act
+    routes = winter.web.find_package_routes('tests.api.package.api_2')
+
+    # Assert
+    assert [route.url_path for route in routes] == ['api_2/', 'api_2/']
diff --git a/winter/application/module_discovery.py b/winter/application/module_discovery.py
index b139d708..8530d294 100644
--- a/winter/application/module_discovery.py
+++ b/winter/application/module_discovery.py
@@ -9,13 +9,14 @@
 
 
 def get_all_classes(package: str) -> Generator[Tuple[str, Type], None, None]:
+    """Classes defined in the modules of a package, or in a single module."""
     classes_set = set()
     for module in import_recursively(package):
         try:
             for class_name, class_ in inspect.getmembers(module, inspect.isclass):
                 if class_ in classes_set:
                     continue
-                if not class_.__module__.startswith(package):
+                if class_.__module__ != package and not class_.__module__.startswith(package + '.'):
                     continue
                 yield class_name, class_
                 classes_set.add(class_)
@@ -41,6 +42,10 @@ def get_all_subclasses(supertype: Type) -> Generator[Tuple[str, Type], None, Non
 
 
 def import_recursively(package: str) -> Generator[ModuleType, None, None]:
+    """Imports and yields the modules of a package and its subpackages, or a single module itself."""
     package = importlib.import_module(package)
+    if not hasattr(package, '__path__'):
+        yield package
+        return
     for loader, name, is_pkg in pkgutil.walk_packages(package.__path__, package.__name__ + '.'):
         yield importlib.import_module(name)
diff --git a/winter/web/autodiscovery.py b/winter/web/autodiscovery.py
index 3c7e7cb2..70ff29ce 100644
--- a/winter/web/autodiscovery.py
+++ b/winter/web/autodiscovery.py
@@ -8,6 +8,7 @@
 
 
 def find_package_routes(package_name: str) -> List[Route]:
+    """Routes of the API classes in a package and its subpackages, or in a single module."""
     import_recursively(package_name)
     routes = []