diff --git a/Cargo.lock b/Cargo.lock
index b8c6a4d4cc0..2a0e607610b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3904,6 +3904,7 @@ version = "0.12.0"
 dependencies = [
  "assert-json-diff",
  "async-trait",
+ "futures",
  "mqtt_channel",
  "mqtt_tests",
  "serde_json",
diff --git a/crates/extensions/tedge_mqtt_ext/Cargo.toml b/crates/extensions/tedge_mqtt_ext/Cargo.toml
index 7255fa9a089..4b003e5f77d 100644
--- a/crates/extensions/tedge_mqtt_ext/Cargo.toml
+++ b/crates/extensions/tedge_mqtt_ext/Cargo.toml
@@ -24,4 +24,5 @@ tedge_utils = { workspace = true }
 tokio = { workspace = true, default_features = false, features = ["macros"] }
 
 [dev-dependencies]
+futures = { workspace = true }
 mqtt_tests = { path = "../../tests/mqtt_tests" }
diff --git a/crates/extensions/tedge_mqtt_ext/src/tests.rs b/crates/extensions/tedge_mqtt_ext/src/tests.rs
index f1400302328..b553cdd1c47 100644
--- a/crates/extensions/tedge_mqtt_ext/src/tests.rs
+++ b/crates/extensions/tedge_mqtt_ext/src/tests.rs
@@ -1,5 +1,6 @@
 use crate::*;
 use mqtt_channel::Topic;
+use std::time::Duration;
 use tedge_actors::Builder;
 use tedge_actors::ServiceConsumer;
 use tedge_actors::SimpleMessageBox;
@@ -19,6 +20,17 @@ impl MqttClientBuilder {
             box_builder: SimpleMessageBoxBuilder::new(name, 16),
         }
     }
+
+    fn new_with_capacity(
+        name: &str,
+        subscriptions: &(impl Clone + Into<TopicFilter>),
+        capacity: usize,
+    ) -> Self {
+        MqttClientBuilder {
+            subscriptions: subscriptions.clone().into(),
+            box_builder: SimpleMessageBoxBuilder::new(name, capacity),
+        }
+    }
 }
 
 impl ServiceConsumer<MqttMessage, MqttMessage, TopicFilter> for MqttClientBuilder {
@@ -47,6 +59,52 @@ impl Builder<MqttClient> for MqttClientBuilder {
     }
 }
 
+#[tokio::test]
+async fn mqtt_actor_can_reliably_forward_messages_under_load() {
+    let broker = mqtt_tests::test_mqtt_broker();
+    let mqtt_config = MqttConfig::default().with_port(broker.port);
+    let mut mqtt = MqttActorBuilder::new(mqtt_config);
+
+    let mut child_device = MqttClientBuilder::new("Child device", &TopicFilter::empty())
+        .with_connection(&mut mqtt)
+        .build();
+
+    let c8y_mapper_topic = Topic::new_unchecked("some/tedge/topic");
+
+    // Simulate a mapper with no message buffer, which will make the problem
+    // occur more quickly if it exists
+    let mut c8y_mapper = MqttClientBuilder::new_with_capacity("C8y mapper", &c8y_mapper_topic, 0)
+        .with_connection(&mut mqtt)
+        .build();
+
+    // Assume Cumulocity just accepts all messages, so don't bother attaching a client
+    let c8y_topic = Topic::new_unchecked("c8y/s/us");
+
+    // Simulate the c8y mapper, forwarding messages from the child device to Cumulocity
+    tokio::spawn(async move {
+        while let Some(mut msg) = c8y_mapper.recv().await {
+            tokio::time::sleep(Duration::from_secs(5)).await;
+            msg.topic = c8y_topic.clone();
+            // If the actor doesn't process incoming/outgoing MQTT messages concurrently,
+            // this will cause a deadlock
+            c8y_mapper.send(msg).await.unwrap();
+        }
+    });
+
+    tokio::spawn(mqtt_actor(mqtt));
+
+    for _ in 1..100 {
+        // This timeout should only be triggered if the actor isn't progressing
+        tokio::time::timeout(
+            Duration::from_millis(50),
+            child_device.send(MqttMessage::new(&c8y_mapper_topic, "Hi Bob")),
+        )
+            .await
+            .expect("messages should be forwarded (is the MQTT actor processing incoming/outgoing messages concurrently?)")
+            .expect("send should succeed");
+    }
+}
+
 #[tokio::test]
 async fn communicate_over_mqtt() {
     let broker = mqtt_tests::test_mqtt_broker();