diff --git a/flow-server/src/main/java/com/vaadin/flow/server/communication/StreamReceiverHandler.java b/flow-server/src/main/java/com/vaadin/flow/server/communication/StreamReceiverHandler.java
index be8c574d559..1f698394fed 100644
--- a/flow-server/src/main/java/com/vaadin/flow/server/communication/StreamReceiverHandler.java
+++ b/flow-server/src/main/java/com/vaadin/flow/server/communication/StreamReceiverHandler.java
@@ -632,11 +632,22 @@ protected Collection<Part> getParts(VaadinRequest request)
 
     protected FileItemIterator getItemIterator(VaadinRequest request)
             throws FileUploadException, IOException {
+        ServletFileUpload upload = createServletFileUpload(request);
+        return upload.getItemIterator((HttpServletRequest) request);
+    }
+
+    // protected for testing purposes only
+    protected ServletFileUpload createServletFileUpload(VaadinRequest request) {
         ServletFileUpload upload = new ServletFileUpload();
         upload.setSizeMax(requestSizeMax);
         upload.setFileSizeMax(fileSizeMax);
         upload.setFileCountMax(fileCountMax);
-        return upload.getItemIterator((HttpServletRequest) request);
+        if (request.getCharacterEncoding() == null) {
+            // Request body's file upload headers are expected to be encoded in
+            // UTF-8 if not explicitly set otherwise in the request.
+            upload.setHeaderEncoding(StandardCharsets.UTF_8.name());
+        }
+        return upload;
     }
 
     public void setRequestSizeMax(long requestSizeMax) {
diff --git a/flow-server/src/test/java/com/vaadin/flow/server/communication/StreamReceiverHandlerTest.java b/flow-server/src/test/java/com/vaadin/flow/server/communication/StreamReceiverHandlerTest.java
index 20569e41bd2..d60b21a0139 100644
--- a/flow-server/src/test/java/com/vaadin/flow/server/communication/StreamReceiverHandlerTest.java
+++ b/flow-server/src/test/java/com/vaadin/flow/server/communication/StreamReceiverHandlerTest.java
@@ -24,6 +24,7 @@
 import java.util.List;
 import java.util.Optional;
 
+import org.apache.commons.fileupload.servlet.ServletFileUpload;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -95,6 +96,7 @@ public class StreamReceiverHandlerTest {
     private List<Part> parts;
 
     private boolean isGetContentLengthLongCalled;
+    private String requestCharacterEncoding;
 
     @Before
     public void setup() throws Exception {
@@ -189,6 +191,11 @@ public long getContentLengthLong() {
                 isGetContentLengthLongCalled = true;
                 return 0;
             }
+
+            @Override
+            public String getCharacterEncoding() {
+                return requestCharacterEncoding;
+            }
         };
     }
 
@@ -299,6 +306,27 @@ public void doHandleMultipartFileUpload_noPart_uploadFailed_responseStatusIs500_
         Assert.assertTrue(isGetContentLengthLongCalled);
     }
 
+    @Test
+    public void createServletFileUpload_useUTF8HeaderCharacterEncodingWhenRequestCharEncodingIsNotSet() {
+        ServletFileUpload servletFileUpload = handler
+                .createServletFileUpload(request);
+        Assert.assertNotNull(servletFileUpload);
+        Assert.assertEquals(
+                "Header encoding should be UTF-8 when request character encoding is null",
+                "UTF-8", servletFileUpload.getHeaderEncoding());
+    }
+
+    @Test
+    public void createServletFileUpload_dontSetHeaderCharEncodingWhenRequestCharEncodingIsSet() {
+        requestCharacterEncoding = "ASCII";
+        ServletFileUpload servletFileUpload = handler
+                .createServletFileUpload(request);
+        Assert.assertNotNull(servletFileUpload);
+        Assert.assertNull(
+                "Header encoding should not be set by Flow when request character encoding is set",
+                servletFileUpload.getHeaderEncoding());
+    }
+
     @Test
     public void doHandleMultipartFileUpload_hasParts_uploadFailed_responseStatusIs500()
             throws IOException {