diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba328bd9a..11052c63d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - #895 patchedast Starred and keyword now consumes their syntactically expected and ** (@lieryan)
 - #896 patchedast cleanup and refactoring (@lieryan)
 - #905 Ignore `node_modules` directories by default when scanning project files and source folders. (@marcoeangeli)
+- #922 Classify autoimport project sources by path containment (@marlon-costa-dc)
 - #926, #929 Raise RefactoringError instead of IndexError/ModuleSyntaxError when extracting an empty or whitespace-only region (@aliassar)
 - #933 Add type annotations to project.py (@lieryan)
 - #119, #928 Fix IndexError in rename and find occurrences when a `from` import is the last thing in a module without a trailing newline (@mcepl)
diff --git a/rope/contrib/autoimport/utils.py b/rope/contrib/autoimport/utils.py
index 11ee6f20e..324ea3173 100644
--- a/rope/contrib/autoimport/utils.py
+++ b/rope/contrib/autoimport/utils.py
@@ -49,7 +49,9 @@ def get_package_source(
     """Detect the source of a given package. Rudimentary implementation."""
     if name in sys.builtin_module_names:
         return Source.BUILTIN
-    if project is not None and project.address in str(package):
+    if project is not None and package.resolve().is_relative_to(
+        project.root.pathlib.resolve()
+    ):
         return Source.PROJECT
     if "site-packages" in package.parts:
         return Source.SITE_PACKAGE
diff --git a/ropetest/contrib/autoimport/utilstest.py b/ropetest/contrib/autoimport/utilstest.py
index 511e1a541..d807debe2 100644
--- a/ropetest/contrib/autoimport/utilstest.py
+++ b/ropetest/contrib/autoimport/utilstest.py
@@ -14,6 +14,25 @@ def test_get_package_source_not_project(mod1_path):
     assert utils.get_package_source(mod1_path, None, "") == Source.UNKNOWN
 
 
+def test_get_package_source_project_prefix_is_not_ancestry(project):
+    sibling = Path(project.address + "-other") / "module.py"
+    assert utils.get_package_source(sibling, project, "module") == Source.UNKNOWN
+
+
+def test_get_package_source_project_sibling(project):
+    sibling = project.root.pathlib.with_name(project.root.pathlib.name + "-other")
+    sibling.mkdir()
+    module = sibling / "outside.py"
+    module.touch()
+    try:
+        assert utils.get_package_source(module, project, "outside") == Source.UNKNOWN
+        escaped = project.root.pathlib / ".." / sibling.name / module.name
+        assert utils.get_package_source(escaped, project, "outside") == Source.UNKNOWN
+    finally:
+        module.unlink()
+        sibling.rmdir()
+
+
 def test_get_package_source_pytest(example_external_package_path):
     # pytest is not installed as part of the standard library
     # but should be installed into site_packages,