diff --git a/openkb/converter.py b/openkb/converter.py
index 710d7a77..2cf72abf 100644
--- a/openkb/converter.py
+++ b/openkb/converter.py
@@ -11,7 +11,6 @@
 from pathlib import Path
 
 import pymupdf
-from markitdown import MarkItDown
 
 from openkb.config import load_config
 from openkb.images import convert_pdf_with_images, copy_relative_images, extract_base64_images
@@ -230,7 +229,15 @@ def convert_document(
             # Use pymupdf dict-mode for PDFs: text + images inline at correct positions
             markdown = convert_pdf_with_images(src, doc_name, images_dir)
         else:
-            # Non-PDF, non-MD: use markitdown (docx, pptx, html, etc.)
+            # Non-PDF, non-MD: use markitdown (docx, pptx, html, etc.).
+            # Imported lazily: markitdown pulls in magika → onnxruntime (tens
+            # of MB, slow to import) that only this branch needs. Keeping it
+            # out of module import makes `import openkb` cheap and lets a
+            # packaged build drop those deps when Office-format ingest isn't
+            # required. markitdown appends warning filters on import but leaves
+            # the CLI's front "ignore" filter in place, so no re-suppress here.
+            from markitdown import MarkItDown
+
             mid = MarkItDown()
             result = mid.convert(str(src), keep_data_uris=True)
             markdown = result.text_content
diff --git a/tests/test_converter.py b/tests/test_converter.py
index 1349b6fb..64adf1b5 100644
--- a/tests/test_converter.py
+++ b/tests/test_converter.py
@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+import subprocess
+import sys
 from unittest.mock import MagicMock, patch
 
 from openkb.converter import convert_document, get_pdf_page_count
@@ -145,7 +147,7 @@ def test_docx_conversion_enables_keep_data_uris(self, kb_dir, tmp_path):
         mock_result.text_content = "![](data:image/png;base64,abc123)"
 
         with (
-            patch("openkb.converter.MarkItDown") as mock_markitdown,
+            patch("markitdown.MarkItDown") as mock_markitdown,
             patch(
                 "openkb.converter.extract_base64_images",
                 return_value="converted markdown",
@@ -164,6 +166,36 @@ def test_docx_conversion_enables_keep_data_uris(self, kb_dir, tmp_path):
         assert result.source_path.read_text(encoding="utf-8") == "converted markdown"
 
 
+# ---------------------------------------------------------------------------
+# Lazy markitdown import (guards the deferred-import optimization)
+# ---------------------------------------------------------------------------
+
+
+class TestLazyMarkItDownImport:
+    def test_importing_converter_does_not_load_markitdown(self):
+        """`import openkb.converter` must not pull in markitdown/magika/onnxruntime.
+
+        markitdown is imported lazily inside convert_document's Office-format
+        branch so `import openkb` stays cheap and a packaged build can drop
+        magika/onnxruntime. This runs in a fresh interpreter (a clean
+        sys.modules) so the assertion is deterministic regardless of what other
+        tests in this process already imported.
+        """
+        heavy = ("markitdown", "magika", "onnxruntime")
+        code = (
+            "import sys, openkb.converter; "
+            f"print(','.join(m for m in {heavy!r} if m in sys.modules))"
+        )
+        proc = subprocess.run(
+            [sys.executable, "-c", code],
+            capture_output=True,
+            text=True,
+        )
+        assert proc.returncode == 0, proc.stderr
+        loaded = proc.stdout.strip()
+        assert loaded == "", f"import openkb.converter eagerly loaded: {loaded}"
+
+
 # ---------------------------------------------------------------------------
 # _registry_path
 # ---------------------------------------------------------------------------