diff --git a/src/core/net/ip6.cpp b/src/core/net/ip6.cpp
index 36b4db582..1f3565606 100644
--- a/src/core/net/ip6.cpp
+++ b/src/core/net/ip6.cpp
@@ -1099,18 +1099,33 @@ void Ip6::DetermineAction(const Message &aMessage,
     {
         // Destination is multicast
 
-        // Forward multicast message to thread unless we received it
-        // on Thread netif.
-
-        aForwardThread = !aMessage.IsOriginThreadNetif();
+        if (aHeader.GetDestination().IsMulticastLargerThanRealmLocal())
+        {
+            // Multicast messages with scope larger than realm-local
+            // use IP-in-IP encapsulation destined to the "All MPL
+            // Forwarders" multicast address. Both the encapsulated
+            // (outer) and embedded (inner) messages are processed.
+            //
+            // For the inner message, we set `aForwardThread` if the
+            // device has a sleepy child that is subscribed to the
+            // destination address. `MeshForwarder::SendMessage()` on
+            // an FTD will then check for this and schedules the
+            // indirect tx to such children. This is skipped on an MTD
+            // (`aForwardThread` remains `false`) since an MTD cannot
+            // have children.
 
 #if OPENTHREAD_FTD
-        if (aMessage.IsOriginThreadNetif() && aHeader.GetDestination().IsMulticastLargerThanRealmLocal() &&
-            Get<ChildTable>().HasSleepyChildWithAddress(aHeader.GetDestination()))
-        {
-            aForwardThread = true;
-        }
+            aForwardThread = Get<ChildTable>().HasSleepyChildWithAddress(aHeader.GetDestination());
 #endif
+        }
+        else
+        {
+            // For all other multicast messages, we forward to the
+            // Thread network unless the message was received on the
+            // Thread netif.
+
+            aForwardThread = !aMessage.IsOriginThreadNetif();
+        }
 
         // Always forward multicast packets to host network stack
         aForwardHost = true;