diff --git a/Cargo.lock b/Cargo.lock
index 39af73a204..d5b51f5010 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5111,6 +5111,7 @@ dependencies = [
  "iox_tests",
  "metric",
  "observability_deps",
+ "paste",
  "tokio",
  "tonic 0.9.2",
  "workspace-hack",
diff --git a/service_grpc_namespace/Cargo.toml b/service_grpc_namespace/Cargo.toml
index e7683835b9..1d7488f45a 100644
--- a/service_grpc_namespace/Cargo.toml
+++ b/service_grpc_namespace/Cargo.toml
@@ -17,4 +17,5 @@ workspace-hack = { version = "0.1", path = "../workspace-hack" }
 assert_matches = "1.5.0"
 iox_tests = { path = "../iox_tests" }
 metric = { path = "../metric" }
+paste = "1.0.12"
 tokio = { version = "1", features = ["rt-multi-thread", "macros"] }
diff --git a/service_grpc_namespace/src/lib.rs b/service_grpc_namespace/src/lib.rs
index 26754f77b2..86bf64b77d 100644
--- a/service_grpc_namespace/src/lib.rs
+++ b/service_grpc_namespace/src/lib.rs
@@ -552,4 +552,123 @@ mod tests {
             );
         assert_eq!(status.code(), Code::InvalidArgument);
     }
+
+    macro_rules! test_create_namespace_name {
+        (
+            $test_name:ident,
+            name = $name:expr,  // The input namespace name string
+            want = $($want:tt)+ // A pattern match against Result<str, tonic::Status>
+                                //    where the Ok variant contains the actual namespace
+                                //    name used on the server side (potentially encoded)
+        ) => {
+            paste::paste! {
+                #[tokio::test]
+                async fn [<test_create_namespace_name_ $test_name>]() {
+                    let catalog: Arc<dyn Catalog> =
+                        Arc::new(MemCatalog::new(Arc::new(metric::Registry::default())));
+
+                    let topic = catalog
+                        .repositories()
+                        .await
+                        .topics()
+                        .create_or_get("kafka-topic")
+                        .await
+                        .unwrap();
+                    let query_pool = catalog
+                        .repositories()
+                        .await
+                        .query_pools()
+                        .create_or_get("query-pool")
+                        .await
+                        .unwrap();
+
+                    let handler = NamespaceService::new(catalog, Some(topic.id), Some(query_pool.id));
+
+                    let req = CreateNamespaceRequest {
+                        name: String::from($name),
+                        retention_period_ns: Some(RETENTION),
+                    };
+
+                    let got = handler.create_namespace(Request::new(req)).await;
+
+                    // Map the result into just the name so it's easier for the
+                    // test to assert the correct namespace name was used.
+                    let actual_name_res = got.as_ref().map(|v| {
+                        v.get_ref()
+                            .namespace
+                            .as_ref()
+                            .expect("no namespace in response")
+                            .name
+                            .as_str()
+                    });
+                    assert_matches!(actual_name_res, $($want)+);
+
+                    // Attempt to list the namespaces
+                    let list = handler
+                        .get_namespaces(Request::new(Default::default()))
+                        .await
+                        .expect("must return namespaces")
+                        .into_inner()
+                        .namespaces;
+
+                    // Validate the expected state - if the request succeeded, then the
+                    // namespace MUST exist.
+                    match got {
+                        Ok(got) => {
+                            assert_matches!(list.as_slice(), [ns] => {
+                                assert_eq!(ns, got.get_ref().namespace.as_ref().unwrap());
+                            })
+                        }
+                        Err(_) => assert!(list.is_empty()),
+                    }
+                }
+            }
+        }
+    }
+
+    test_create_namespace_name!(ok, name = "bananas", want = Ok("bananas"));
+
+    test_create_namespace_name!(multi_byte, name = "🍌", want = Ok("🍌"));
+
+    test_create_namespace_name!(
+        tab,
+        name = "it\tis\ttabtasitc",
+        want = Err(e) => {
+            assert_eq!(e.code(), Code::InvalidArgument);
+            assert_eq!(e.message(), "namespace name 'it\tis\ttabtasitc' contains invalid character, character number 2 is a control which is not allowed");
+        }
+    );
+
+    test_create_namespace_name!(
+        null,
+        name = "bad \0 bananas",
+        want = Err(e) => {
+            assert_eq!(e.code(), Code::InvalidArgument);
+            assert_eq!(e.message(), "namespace name 'bad \0 bananas' contains invalid character, character number 4 is a control which is not allowed");
+        }
+    );
+
+    test_create_namespace_name!(
+        length_lower,
+        name = "",
+        want = Err(e) => {
+            assert_eq!(e.code(), Code::InvalidArgument);
+            assert_eq!(e.message(), r#"namespace name  length must be between 1 and 64 characters"#);
+        }
+    );
+
+    test_create_namespace_name!(
+        length_upper_inclusive,
+        name = "A".repeat(64),
+        want = Ok(v) if v == "A".repeat(64)
+    );
+
+    test_create_namespace_name!(
+        length_upper_exclusive,
+        name = "A".repeat(65),
+        want = Err(e) => {
+            assert_eq!(e.code(), Code::InvalidArgument);
+            assert_eq!(e.message(), r#"namespace name AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA length must be between 1 and 64 characters"#);
+        }
+    );
 }