diff --git a/AUTHORS b/AUTHORS
index 9be48958485..6e59e98be10 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -134,6 +134,7 @@ Deysha Rivera
 Dheeraj C K
 Dhiren Serai
 Diego Russo
+Dima Gerasimov
 Dmitry Dygalo
 Dmitry Pribysh
 Dominic Mortlock
diff --git a/changelog/478.feature.rst b/changelog/478.feature.rst
new file mode 100644
index 00000000000..28935bea866
--- /dev/null
+++ b/changelog/478.feature.rst
@@ -0,0 +1 @@
+Support PEP420 (implicit namespace packages) as `--pyargs` target.
diff --git a/src/_pytest/main.py b/src/_pytest/main.py
index dac084b553a..98027584f3d 100644
--- a/src/_pytest/main.py
+++ b/src/_pytest/main.py
@@ -991,11 +991,19 @@ def search_pypath(module_name: str) -> str | None:
     # ValueError: not a module name
     except (AttributeError, ImportError, ValueError):
         return None
-    if spec is None or spec.origin is None or spec.origin == "namespace":
+
+    if spec is None:
         return None
-    elif spec.submodule_search_locations:
-        return os.path.dirname(spec.origin)
+    elif (
+        spec.submodule_search_locations is not None
+        and len(spec.submodule_search_locations) > 0
+    ):
+        # If submodule_search_locations is set, it's a package (regular or namespace).
+        # Typically there is a single entry, but documentation claims it can be empty too
+        #  (e.g. if the package has no physical location).
+        return spec.submodule_search_locations[0]
     else:
+        # Must be a simple module.
         return spec.origin
 
 
diff --git a/testing/test_main.py b/testing/test_main.py
index 94eac02ce63..3d8d6adc35e 100644
--- a/testing/test_main.py
+++ b/testing/test_main.py
@@ -169,8 +169,13 @@ def test_dir(self, invocation_path: Path) -> None:
         ):
             resolve_collection_argument(invocation_path, "src/pkg::foo::bar")
 
-    def test_pypath(self, invocation_path: Path) -> None:
+    @pytest.mark.parametrize("namespace_package", [False, True])
+    def test_pypath(self, namespace_package: bool, invocation_path: Path) -> None:
         """Dotted name and parts."""
+        if namespace_package:
+            # Namespace package doesn't have to contain __init__py
+            (invocation_path / "src/pkg/__init__.py").unlink()
+
         assert resolve_collection_argument(
             invocation_path, "pkg.test", as_pypath=True
         ) == CollectionArgument(