diff --git a/python_multipart/multipart.py b/python_multipart/multipart.py
index f4e2cea..be936fc 100644
--- a/python_multipart/multipart.py
+++ b/python_multipart/multipart.py
@@ -212,8 +212,8 @@ def _parseparam(s: str) -> list[str]:
         if i == -1:
             f = s[start:end]
         else:
-            f = s[start:i].rstrip().lower() + "=" + s[i + 1 : end].lstrip()
-        plist.append(f.strip())
+            f = s[start:i].rstrip(" \t").lower() + "=" + s[i + 1 : end].lstrip(" \t")
+        plist.append(f.strip(" \t"))
         start = end
     return plist
 
@@ -232,7 +232,7 @@ def parse_options_header(value: str | bytes | None) -> tuple[bytes, dict[bytes,
 
     # If we have no options, return the string as-is.
     if ";" not in value:
-        return (value.lower().strip().encode("latin-1"), {})
+        return (value.lower().strip(" \t").encode("latin-1"), {})
 
     ctype, *segments = _parseparam(value)
     options: dict[bytes, bytes] = {}
diff --git a/tests/test_data/http/non_ascii_whitespace_before_filename.http b/tests/test_data/http/non_ascii_whitespace_before_filename.http
new file mode 100644
index 0000000..7d06847
--- /dev/null
+++ b/tests/test_data/http/non_ascii_whitespace_before_filename.http
@@ -0,0 +1,9 @@
+------boundary
+Content-Disposition: form-data; name="a"; filename="a.txt"
+
+first
+------boundary
+Content-Disposition: form-data; name="b";…filename="b.txt"
+
+second
+------boundary--
diff --git a/tests/test_data/http/non_ascii_whitespace_before_filename.yaml b/tests/test_data/http/non_ascii_whitespace_before_filename.yaml
new file mode 100644
index 0000000..8f084e0
--- /dev/null
+++ b/tests/test_data/http/non_ascii_whitespace_before_filename.yaml
@@ -0,0 +1,8 @@
+boundary: ----boundary
+expected:
+  - name: a
+    type: field
+    data: !!binary "Zmlyc3Q="
+  - name: b
+    type: field
+    data: !!binary "c2Vjb25k"
diff --git a/tests/test_multipart.py b/tests/test_multipart.py
index e2ad6ca..31b84e3 100644
--- a/tests/test_multipart.py
+++ b/tests/test_multipart.py
@@ -272,6 +272,14 @@ def test_single_param_with_spaces(self) -> None:
         self.assertEqual(t, b"application/json")
         self.assertEqual(p, {b"par": b"val"})
 
+    def test_tabs_around_param_are_trimmed(self) -> None:
+        _, p = parse_options_header(b"application/json;\t par \t=\t val\t")
+        self.assertEqual(p, {b"par": b"val"})
+
+    def test_non_breaking_space_is_not_trimmed(self) -> None:
+        _, p = parse_options_header(b"form-data; name=voil\xc3\xa0")
+        self.assertEqual(p, {b"name": b"voil\xc3\xa0"})
+
     def test_multiple_params(self) -> None:
         t, p = parse_options_header(b"application/json;par=val;asdf=foo")
         self.assertEqual(t, b"application/json")