diff --git a/CHANGELOG.md b/CHANGELOG.md
index e5adea82..1a3deccb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* `JsonObject::createNestedObject()` returns `JsonObject::invalid()` if key is null (issue #1891)
+
 v5.13.5
 -------
 
diff --git a/src/ArduinoJson/JsonObjectImpl.hpp b/src/ArduinoJson/JsonObjectImpl.hpp
index 060bff1f..7d3a4c84 100644
--- a/src/ArduinoJson/JsonObjectImpl.hpp
+++ b/src/ArduinoJson/JsonObjectImpl.hpp
@@ -22,7 +22,9 @@ template <typename TStringRef>
 inline JsonObject &JsonObject::createNestedObject_impl(TStringRef key) {
   if (!_buffer) return JsonObject::invalid();
   JsonObject &object = _buffer->createObject();
-  set(key, object);
-  return object;
+  if (set(key, object))
+    return object;
+  else
+    return JsonObject::invalid();
 }
 }  // namespace ArduinoJson
diff --git a/test/JsonObject/CMakeLists.txt b/test/JsonObject/CMakeLists.txt
index 7a318ff1..d1c0547d 100644
--- a/test/JsonObject/CMakeLists.txt
+++ b/test/JsonObject/CMakeLists.txt
@@ -2,9 +2,10 @@
 # Copyright Benoit Blanchon 2014-2023
 # MIT License
 
-add_executable(JsonObjectTests 
+add_executable(JsonObjectTests
 	basics.cpp
 	containsKey.cpp
+	createNestedObject.cpp
 	get.cpp
 	invalid.cpp
 	iterator.cpp
diff --git a/test/JsonObject/createNestedObject.cpp b/test/JsonObject/createNestedObject.cpp
new file mode 100644
index 00000000..8da784f7
--- /dev/null
+++ b/test/JsonObject/createNestedObject.cpp
@@ -0,0 +1,23 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2023
+// MIT License
+
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("JsonObject::createNestedObject()") {
+  DynamicJsonBuffer _jsonBuffer;
+  JsonObject& _object = _jsonBuffer.createObject();
+
+  SECTION("success() should return true if key is non-null") {
+    JsonObject& obj = _object.createNestedObject("key");
+    REQUIRE(obj.success() == true);
+  }
+
+  SECTION("success() should return false if key is null") {
+    const char* null = 0;
+    JsonObject& obj = _object.createNestedObject(null);
+    REQUIRE(obj.success() == false);
+  }
+}