diff --git a/change/react-native-windows-4090a69c-674e-42d3-a643-39ec206c7c00.json b/change/react-native-windows-4090a69c-674e-42d3-a643-39ec206c7c00.json
new file mode 100644
index 00000000000..1fed4496d44
--- /dev/null
+++ b/change/react-native-windows-4090a69c-674e-42d3-a643-39ec206c7c00.json
@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Set Origin HTTP header during CORS (#10700)",
+  "packageName": "react-native-windows",
+  "email": "julio.rocha@microsoft.com",
+  "dependentChangeType": "patch"
+}
diff --git a/vnext/Shared/Networking/OriginPolicyHttpFilter.cpp b/vnext/Shared/Networking/OriginPolicyHttpFilter.cpp
index 460b5d00f0f..15d23ec1b5b 100644
--- a/vnext/Shared/Networking/OriginPolicyHttpFilter.cpp
+++ b/vnext/Shared/Networking/OriginPolicyHttpFilter.cpp
@@ -754,6 +754,11 @@ ResponseOperation OriginPolicyHttpFilter::SendRequestAsync(HttpRequestMessage co
       ValidatePreflightResponse(coRequest, preflightResponse);
     }
 
+    if (originPolicy == OriginPolicy::SimpleCrossOriginResourceSharing ||
+        originPolicy == OriginPolicy::CrossOriginResourceSharing) {
+      coRequest.Headers().Insert(L"Origin", s_origin.AbsoluteCanonicalUri());
+    }
+
     auto response = co_await m_innerFilter.SendRequestAsync(coRequest);
 
     ValidateResponse(response, originPolicy);