diff --git a/foamlib/_files/_parsing.py b/foamlib/_files/_parsing.py
index 4b218b1..72d8172 100644
--- a/foamlib/_files/_parsing.py
+++ b/foamlib/_files/_parsing.py
@@ -89,7 +89,7 @@ def _parse_ascii_field(
         s = re.sub(ignore.re, " ", s)
     s = s.replace("(", " ").replace(")", " ")
 
-    return np.fromstring(s, sep=" ").reshape(-1, *tensor_kind.shape)
+    return np.fromstring(s, sep=" ").reshape(-1, *tensor_kind.shape)  # type: ignore [return-value]
 
 
 def _unpack_binary_field(
@@ -99,7 +99,7 @@ def _unpack_binary_field(
     assert float_size in (4, 8)
 
     dtype = np.float32 if float_size == 4 else float
-    return np.frombuffer(b, dtype=dtype).reshape(-1, *tensor_kind.shape)
+    return np.frombuffer(b, dtype=dtype).reshape(-1, *tensor_kind.shape)  # type: ignore [return-value]
 
 
 def _tensor_list(
diff --git a/foamlib/_files/_serialization.py b/foamlib/_files/_serialization.py
index 9e9380f..54fec4d 100644
--- a/foamlib/_files/_serialization.py
+++ b/foamlib/_files/_serialization.py
@@ -50,7 +50,7 @@ def normalize(data: Entry, *, kind: Kind = Kind.DEFAULT) -> Entry:
                     arr = arr.astype(float)
 
                 if arr.ndim == 1 or (arr.ndim == 2 and arr.shape[1] in (3, 6, 9)):
-                    return arr
+                    return arr  # type: ignore [return-value]
 
             return data
 
diff --git a/foamlib/_files/_types.py b/foamlib/_files/_types.py
index 8fefa7e..3cb6e41 100644
--- a/foamlib/_files/_types.py
+++ b/foamlib/_files/_types.py
@@ -79,7 +79,7 @@ class Dimensioned:
 
     def __post_init__(self) -> None:
         if is_sequence(self.value):
-            self.value = np.asarray(self.value, dtype=float)
+            self.value = np.asarray(self.value, dtype=float)  # type: ignore [assignment]
         else:
             assert isinstance(self.value, (int, float, np.ndarray))
             self.value = float(self.value)
diff --git a/tests/test_files/test_dumps.py b/tests/test_files/test_dumps.py
index b7a0b60..90c159a 100644
--- a/tests/test_files/test_dumps.py
+++ b/tests/test_files/test_dumps.py
@@ -37,7 +37,7 @@ def test_serialize_data() -> None:
         == b"nonuniform List<vector> 2(\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x08@\x00\x00\x00\x00\x00\x00\x10@\x00\x00\x00\x00\x00\x00\x14@\x00\x00\x00\x00\x00\x00\x18@)"
     )
     assert (
-        dumps(np.array([1, 2], dtype=np.float32), kind=Kind.BINARY_FIELD)
+        dumps(np.array([1, 2], dtype=np.float32), kind=Kind.BINARY_FIELD)   # type: ignore [arg-type]
         == b"nonuniform List<scalar> 2(\x00\x00\x80?\x00\x00\x00@)"
     )
     assert (
diff --git a/tests/test_files/test_files.py b/tests/test_files/test_files.py
index 964d507..0f88ca9 100644
--- a/tests/test_files/test_files.py
+++ b/tests/test_files/test_files.py
@@ -163,19 +163,19 @@ def test_internal_field(cavity: FoamCase) -> None:
     p_arr = np.zeros(size)
     U_arr = np.zeros((size, 3))
 
-    cavity[0]["p"].internal_field = p_arr
-    cavity[0]["U"].internal_field = U_arr
+    cavity[0]["p"].internal_field = p_arr  # type: ignore [assignment]
+    cavity[0]["U"].internal_field = U_arr  # type: ignore [assignment]
 
     assert cavity[0]["p"].internal_field == pytest.approx(p_arr)
     U = cavity[0]["U"].internal_field
     assert isinstance(U, np.ndarray)
     assert U_arr == pytest.approx(U)
 
-    p_arr = np.arange(size) * 1e-6
+    p_arr = np.arange(size) * 1e-6  # type: ignore [assignment]
     U_arr = np.full((size, 3), [-1e-6, 1e-6, 0]) * np.arange(size)[:, np.newaxis]
 
-    cavity[0]["p"].internal_field = p_arr
-    cavity[0]["U"].internal_field = U_arr
+    cavity[0]["p"].internal_field = p_arr  # type: ignore [assignment]
+    cavity[0]["U"].internal_field = U_arr  # type: ignore [assignment]
 
     assert cavity[0]["p"].internal_field == pytest.approx(p_arr)
     U = cavity[0]["U"].internal_field
@@ -210,7 +210,7 @@ def test_binary_field(cavity: FoamCase) -> None:
     p_arr = np.arange(len(p_bin)) * 1e-6
     U_arr = np.full_like(U_bin, [-1e-6, 1e-6, 0]) * np.arange(len(U_bin))[:, np.newaxis]
 
-    cavity[0]["p"].internal_field = p_arr
+    cavity[0]["p"].internal_field = p_arr  # type: ignore [assignment]
     cavity[0]["U"].internal_field = U_arr
 
     assert cavity[0]["p"].internal_field == pytest.approx(p_arr)
@@ -237,7 +237,7 @@ def test_compressed_field(cavity: FoamCase) -> None:
     p_arr = np.arange(len(p_bin)) * 1e-6
     U_arr = np.full_like(U_bin, [-1e-6, 1e-6, 0]) * np.arange(len(U_bin))[:, np.newaxis]
 
-    cavity[0]["p"].internal_field = p_arr
+    cavity[0]["p"].internal_field = p_arr  # type: ignore [assignment]
     cavity[0]["U"].internal_field = U_arr
 
     assert cavity[0]["p"].internal_field == pytest.approx(p_arr)