diff --git a/src/pysparkplug/_datatype.py b/src/pysparkplug/_datatype.py
index 0bd3c3d..01f51f0 100644
--- a/src/pysparkplug/_datatype.py
+++ b/src/pysparkplug/_datatype.py
@@ -122,10 +122,13 @@ def _int_encoder(value: int, bits: int) -> int:
 
 
 def _int_decoder(value: int, bits: int) -> int:
-    max_val: int = 2**bits
-    if not 0 <= value < max_val:
-        raise OverflowError(f"Int{bits} overflow with value {value}")
-    return value - (max_val if value >= 2 ** (bits - 1) else 0)
+    mask = (1 << bits) - 1  # e.g. 0xFFFF for 16 bits
+    value &= mask  # drop any higher bits
+    sign_bit = 1 << (bits - 1)  # e.g. 0x8000 for 16 bits
+    if value & sign_bit:  # if sign bit is set
+        value -= 1 << bits
+
+    return value
 
 
 def _encode_numeric_array(values: Sequence[float], format_char: str) -> bytes:
diff --git a/test/unit_tests/test_datatype.py b/test/unit_tests/test_datatype.py
index 37026b6..9244da1 100644
--- a/test/unit_tests/test_datatype.py
+++ b/test/unit_tests/test_datatype.py
@@ -134,11 +134,15 @@ def test_integer_encoding(self):
                         decoded, value, f"Failed to encode/decode {value} with {dtype}"
                     )
 
-    def test_decoder_errors(self) -> None:
-        with self.assertRaises(OverflowError):
-            # too large
-            DataType.INT8.decode(2**9)
+    def test_decoding_sign_extended_values(self):
+        value = -87
+        signExtendedValue = (
+            value & 0xFFFFFFFF  # packed into uint32 for Google Protobuf
+        )
+        decoded = DataType.INT16.decode(signExtendedValue)
+        self.assertEqual(decoded, value)
 
+    def test_decoder_errors(self) -> None:
         with self.assertRaises(ValueError):
             # not enough bytes
             DataType.INT16_ARRAY.decode(b"\x00")