diff --git a/build.py b/build.py
index 79aee76..4f88215 100644
--- a/build.py
+++ b/build.py
@@ -56,6 +56,17 @@ def build(build: bool = True, copy: bool = True, test: bool = False, dest: str |
                         for f in runtime_dir.rglob("*.dll"):
                             # PyInstaller on Windows expects 'src;dest'
                             add_binary_args += ["--add-binary", f"{str(f)};pythonnet\\runtime"]
+                    # also include the full pythonnet package folder as data so
+                    # package-relative lookups succeed at runtime
+                    add_data_args += ["--add-data", f"{str(pn_path)};pythonnet"]
+                    # try to include clr_loader package as well
+                    try:
+                        spec_clr = importlib.util.find_spec("clr_loader")
+                        if spec_clr and spec_clr.submodule_search_locations:
+                            clr_path = Path(spec_clr.submodule_search_locations[0])
+                            add_data_args += ["--add-data", f"{str(clr_path)};clr_loader"]
+                    except Exception:
+                        pass
             except Exception as e:
                 print(f"Warning: couldn't locate pythonnet runtime: {e}")