diff --git a/include/ArduinoJson/ForwardDeclarations.hpp b/include/ArduinoJson/ForwardDeclarations.hpp
deleted file mode 100644
index 1ca4b297..00000000
--- a/include/ArduinoJson/ForwardDeclarations.hpp
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright Benoit Blanchon 2014
-// MIT License
-//
-// Arduino JSON library
-// https://github.com/bblanchon/ArduinoJson
-
-#pragma once
-
-namespace ArduinoJson {
-class JsonArray;
-class JsonBuffer;
-class JsonObject;
-
-namespace Internals {
-class IndentedPrint;
-class JsonWriter;
-}
-}
diff --git a/include/ArduinoJson/Internals/JsonValueContent.hpp b/include/ArduinoJson/Internals/JsonValueContent.hpp
index 59ebcec1..af9b7c08 100644
--- a/include/ArduinoJson/Internals/JsonValueContent.hpp
+++ b/include/ArduinoJson/Internals/JsonValueContent.hpp
@@ -6,9 +6,11 @@
 
 #pragma once
 
-#include "../ForwardDeclarations.hpp"
-
 namespace ArduinoJson {
+
+class JsonArray;
+class JsonObject;
+
 namespace Internals {
 
 union JsonValueContent {
diff --git a/include/ArduinoJson/JsonArray.hpp b/include/ArduinoJson/JsonArray.hpp
index 30e4bea7..111ec23a 100644
--- a/include/ArduinoJson/JsonArray.hpp
+++ b/include/ArduinoJson/JsonArray.hpp
@@ -6,18 +6,19 @@
 
 #pragma once
 
-#include "ForwardDeclarations.hpp"
-#include "JsonArrayIterator.hpp"
-#include "JsonArrayConstIterator.hpp"
-#include "JsonPrintable.hpp"
-#include "JsonObject.hpp"
 #include "Internals/ReferenceType.hpp"
+#include "JsonArrayConstIterator.hpp"
+#include "JsonArrayIterator.hpp"
+#include "JsonPrintable.hpp"
 
 #define JSON_ARRAY_SIZE(NUMBER_OF_ELEMENTS) \
   (sizeof(JsonArray) + (NUMBER_OF_ELEMENTS) * sizeof(Internals::JsonArrayNode))
 
 namespace ArduinoJson {
 
+class JsonObject;
+class JsonBuffer;
+
 class JsonArray : public JsonPrintable, public Internals::ReferenceType {
   friend class JsonBuffer;
 
diff --git a/include/ArduinoJson/JsonBuffer.hpp b/include/ArduinoJson/JsonBuffer.hpp
index b16a321d..65ed2b72 100644
--- a/include/ArduinoJson/JsonBuffer.hpp
+++ b/include/ArduinoJson/JsonBuffer.hpp
@@ -6,10 +6,11 @@
 
 #pragma once
 
-#include "ForwardDeclarations.hpp"
 #include "JsonValue.hpp"
 
 namespace ArduinoJson {
+class JsonArray;
+class JsonObject;
 
 class JsonBuffer {
  public:
diff --git a/include/ArduinoJson/JsonObject.hpp b/include/ArduinoJson/JsonObject.hpp
index 6243e591..346ad3a4 100644
--- a/include/ArduinoJson/JsonObject.hpp
+++ b/include/ArduinoJson/JsonObject.hpp
@@ -6,9 +6,7 @@
 
 #pragma once
 
-#include "Internals/JsonObjectNode.hpp"
 #include "Internals/ReferenceType.hpp"
-#include "JsonArray.hpp"
 #include "JsonObjectConstIterator.hpp"
 #include "JsonObjectIterator.hpp"
 #include "JsonPrintable.hpp"
@@ -19,6 +17,9 @@
 
 namespace ArduinoJson {
 
+class JsonArray;
+class JsonBuffer;
+
 class JsonObject : public JsonPrintable, public Internals::ReferenceType {
   friend class JsonBuffer;
 
diff --git a/include/ArduinoJson/JsonPair.hpp b/include/ArduinoJson/JsonPair.hpp
index 7176e496..670bdef9 100644
--- a/include/ArduinoJson/JsonPair.hpp
+++ b/include/ArduinoJson/JsonPair.hpp
@@ -7,7 +7,6 @@
 #pragma once
 
 #include "JsonValue.hpp"
-#include "Internals/JsonObjectNode.hpp"
 
 namespace ArduinoJson {
 
@@ -17,4 +16,4 @@ struct JsonPair {
   const char* key;
   JsonValue value;
 };
-}
\ No newline at end of file
+}
diff --git a/include/ArduinoJson/JsonPrintable.hpp b/include/ArduinoJson/JsonPrintable.hpp
index 8e6d2714..39656922 100644
--- a/include/ArduinoJson/JsonPrintable.hpp
+++ b/include/ArduinoJson/JsonPrintable.hpp
@@ -6,11 +6,15 @@
 
 #pragma once
 
-#include "ForwardDeclarations.hpp"
 #include "Arduino/Printable.hpp"
 
 namespace ArduinoJson {
 
+namespace Internals {
+class IndentedPrint;
+class JsonWriter;
+}
+
 class JsonPrintable : public Printable {
  public:
   size_t printTo(char *buffer, size_t bufferSize) const;
diff --git a/include/ArduinoJson/JsonValue.hpp b/include/ArduinoJson/JsonValue.hpp
index 2a5c9a2b..7d469061 100644
--- a/include/ArduinoJson/JsonValue.hpp
+++ b/include/ArduinoJson/JsonValue.hpp
@@ -8,11 +8,18 @@
 
 #include <stddef.h>
 
-#include "ForwardDeclarations.hpp"
 #include "Internals/JsonValueContent.hpp"
 #include "Internals/JsonValueType.hpp"
 
 namespace ArduinoJson {
+
+class JsonArray;
+class JsonObject;
+
+namespace Internals {
+class JsonWriter;
+}
+
 class JsonValue {
  public:
   JsonValue() : _type(Internals::JSON_UNDEFINED) {}