diff --git a/src/main/java/org/apache/commons/io/input/MemoryMappedFileInputStream.java b/src/main/java/org/apache/commons/io/input/MemoryMappedFileInputStream.java
index a1f5d2144b7..b9ca1191b02 100644
--- a/src/main/java/org/apache/commons/io/input/MemoryMappedFileInputStream.java
+++ b/src/main/java/org/apache/commons/io/input/MemoryMappedFileInputStream.java
@@ -234,7 +234,7 @@ public int read() throws IOException {
                 return EOF;
             }
         }
-        return Short.toUnsignedInt(buffer.get());
+        return buffer.get() & 0xFF;
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/io/input/MemoryMappedFileInputStreamTest.java b/src/test/java/org/apache/commons/io/input/MemoryMappedFileInputStreamTest.java
index 471874f1ee3..ebb5ef0e8fb 100644
--- a/src/test/java/org/apache/commons/io/input/MemoryMappedFileInputStreamTest.java
+++ b/src/test/java/org/apache/commons/io/input/MemoryMappedFileInputStreamTest.java
@@ -211,6 +211,18 @@ void testReadAfterClose(final int len) throws Exception {
         }
     }
 
+    @Test
+    void testReadSingleByteIsUnsigned() throws IOException {
+        final byte[] expectedData = { 0x00, 0x01, 0x7F, (byte) 0x80, (byte) 0xAB, (byte) 0xFE, (byte) 0xFF };
+        final Path file = Files.write(Files.createTempFile(tempDir, null, null), expectedData);
+        try (InputStream inputStream = newInputStream(file, 4)) {
+            for (final byte expected : expectedData) {
+                assertEquals(expected & 0xFF, inputStream.read());
+            }
+            assertEquals(IOUtils.EOF, inputStream.read());
+        }
+    }
+
     @Test
     void testReadSingleByte() throws IOException {
         // setup