diff --git a/objectivec/GPBArray_PackagePrivate.h b/objectivec/GPBArray_PackagePrivate.h
index 7add7d7b7d..0f970824e9 100644
--- a/objectivec/GPBArray_PackagePrivate.h
+++ b/objectivec/GPBArray_PackagePrivate.h
@@ -7,7 +7,7 @@
 
 #import "GPBArray.h"
 
-@class GPBMessage;
+#import "GPBMessage.h"
 
 //%PDDM-DEFINE DECLARE_ARRAY_EXTRAS()
 //%ARRAY_INTERFACE_EXTRAS(Int32, int32_t)
diff --git a/objectivec/GPBCodedInputStream.h b/objectivec/GPBCodedInputStream.h
index c0015d04af..530b1cbb0e 100644
--- a/objectivec/GPBCodedInputStream.h
+++ b/objectivec/GPBCodedInputStream.h
@@ -9,7 +9,7 @@
 
 #import "GPBExtensionRegistry.h"
 
-@class GPBMessage;
+#import "GPBMessage.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
diff --git a/objectivec/GPBCodedInputStream_PackagePrivate.h b/objectivec/GPBCodedInputStream_PackagePrivate.h
index b2f8f8e50f..b6b77b50e2 100644
--- a/objectivec/GPBCodedInputStream_PackagePrivate.h
+++ b/objectivec/GPBCodedInputStream_PackagePrivate.h
@@ -11,8 +11,10 @@
 
 #import "GPBCodedInputStream.h"
 
+#import "GPBDescriptor.h"
+#import "GPBUnknownFieldSet.h"
+
 @class GPBUnknownFieldSet;
-@class GPBFieldDescriptor;
 
 typedef struct GPBCodedInputStreamState {
   const uint8_t *bytes;
diff --git a/objectivec/GPBCodedOutputStream.h b/objectivec/GPBCodedOutputStream.h
index 3e14517011..3461fa95e0 100644
--- a/objectivec/GPBCodedOutputStream.h
+++ b/objectivec/GPBCodedOutputStream.h
@@ -10,15 +10,9 @@
 #import "GPBRuntimeTypes.h"
 #import "GPBWireFormat.h"
 
-@class GPBBoolArray;
-@class GPBDoubleArray;
-@class GPBEnumArray;
-@class GPBFloatArray;
-@class GPBMessage;
-@class GPBInt32Array;
-@class GPBInt64Array;
-@class GPBUInt32Array;
-@class GPBUInt64Array;
+#import "GPBArray.h"
+#import "GPBUnknownFieldSet.h"
+
 @class GPBUnknownFieldSet;
 
 NS_ASSUME_NONNULL_BEGIN
diff --git a/objectivec/GPBCodedOutputStream_PackagePrivate.h b/objectivec/GPBCodedOutputStream_PackagePrivate.h
index 208ad9e11b..3cadb55680 100644
--- a/objectivec/GPBCodedOutputStream_PackagePrivate.h
+++ b/objectivec/GPBCodedOutputStream_PackagePrivate.h
@@ -5,8 +5,12 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
+#import <Foundation/Foundation.h>
+
 #import "GPBCodedOutputStream.h"
 
+#import "GPBMessage.h"
+
 NS_ASSUME_NONNULL_BEGIN
 
 CF_EXTERN_C_BEGIN
diff --git a/objectivec/GPBDictionary_PackagePrivate.h b/objectivec/GPBDictionary_PackagePrivate.h
index 2800db1f1e..8d6ea16c95 100644
--- a/objectivec/GPBDictionary_PackagePrivate.h
+++ b/objectivec/GPBDictionary_PackagePrivate.h
@@ -9,10 +9,10 @@
 
 #import "GPBDictionary.h"
 
-@class GPBCodedInputStream;
-@class GPBCodedOutputStream;
-@protocol GPBExtensionRegistry;
-@class GPBFieldDescriptor;
+#import "GPBCodedInputStream.h"
+#import "GPBCodedOutputStream.h"
+#import "GPBDescriptor.h"
+#import "GPBExtensionRegistry.h"
 
 @protocol GPBDictionaryInternalsProtocol
 - (size_t)computeSerializedSizeAsField:(GPBFieldDescriptor *)field;
diff --git a/objectivec/GPBExtensionInternals.h b/objectivec/GPBExtensionInternals.h
index d944da0546..4bd4a5b2b5 100644
--- a/objectivec/GPBExtensionInternals.h
+++ b/objectivec/GPBExtensionInternals.h
@@ -7,11 +7,12 @@
 
 #import <Foundation/Foundation.h>
 
+#import "GPBCodedOutputStream.h"
 #import "GPBDescriptor.h"
 
-@class GPBCodedOutputStream;
+size_t GPBComputeExtensionSerializedSizeIncludingTag(
+    GPBExtensionDescriptor *extension, id value);
 
-size_t GPBComputeExtensionSerializedSizeIncludingTag(GPBExtensionDescriptor *extension, id value);
-
-void GPBWriteExtensionValueToOutputStream(GPBExtensionDescriptor *extension, id value,
+void GPBWriteExtensionValueToOutputStream(GPBExtensionDescriptor *extension,
+                                          id value,
                                           GPBCodedOutputStream *output);
diff --git a/objectivec/GPBExtensionRegistry.h b/objectivec/GPBExtensionRegistry.h
index c1f1809be8..9ca8ae5336 100644
--- a/objectivec/GPBExtensionRegistry.h
+++ b/objectivec/GPBExtensionRegistry.h
@@ -7,8 +7,7 @@
 
 #import <Foundation/Foundation.h>
 
-@class GPBDescriptor;
-@class GPBExtensionDescriptor;
+#import "GPBDescriptor.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
diff --git a/objectivec/GPBMessage.h b/objectivec/GPBMessage.h
index 2fbc797bf6..5c49a58de8 100644
--- a/objectivec/GPBMessage.h
+++ b/objectivec/GPBMessage.h
@@ -8,13 +8,15 @@
 #import <Foundation/Foundation.h>
 
 #import "GPBBootstrap.h"
+#import "GPBCodedInputStream.h"
+#import "GPBCodedOutputStream.h"
+#import "GPBDescriptor.h"
 #import "GPBExtensionRegistry.h"
+#import "GPBUnknownFieldSet.h"
+#import "GPBUnknownFields.h"
 
-@class GPBDescriptor;
 @class GPBCodedInputStream;
 @class GPBCodedOutputStream;
-@class GPBExtensionDescriptor;
-@class GPBFieldDescriptor;
 @class GPBUnknownFieldSet;
 @class GPBUnknownFields;
 
diff --git a/objectivec/GPBRootObject.h b/objectivec/GPBRootObject.h
index 5c692122b5..b31f5b7842 100644
--- a/objectivec/GPBRootObject.h
+++ b/objectivec/GPBRootObject.h
@@ -7,7 +7,7 @@
 
 #import <Foundation/Foundation.h>
 
-@class GPBExtensionRegistry;
+#import "GPBExtensionRegistry.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
diff --git a/objectivec/GPBRootObject_PackagePrivate.h b/objectivec/GPBRootObject_PackagePrivate.h
index fcae7c2c5e..561c935b4f 100644
--- a/objectivec/GPBRootObject_PackagePrivate.h
+++ b/objectivec/GPBRootObject_PackagePrivate.h
@@ -9,7 +9,7 @@
 
 #import "GPBRootObject.h"
 
-@class GPBExtensionDescriptor;
+#import "GPBDescriptor.h"
 
 @interface GPBRootObject ()
 
diff --git a/objectivec/GPBRuntimeTypes.h b/objectivec/GPBRuntimeTypes.h
index 5373410d55..440628a342 100644
--- a/objectivec/GPBRuntimeTypes.h
+++ b/objectivec/GPBRuntimeTypes.h
@@ -11,7 +11,6 @@
 
 @class GPBEnumDescriptor;
 @class GPBMessage;
-@class GPBInt32Array;
 
 /**
  * Verifies that a given value can be represented by an enum type.
diff --git a/objectivec/GPBUnknownField.h b/objectivec/GPBUnknownField.h
index 6728ed0830..e4dd0596fa 100644
--- a/objectivec/GPBUnknownField.h
+++ b/objectivec/GPBUnknownField.h
@@ -7,9 +7,10 @@
 
 #import <Foundation/Foundation.h>
 
-@class GPBCodedOutputStream;
-@class GPBUInt32Array;
-@class GPBUInt64Array;
+#import "GPBArray.h"
+#import "GPBUnknownFieldSet.h"
+#import "GPBUnknownFields.h"
+
 @class GPBUnknownFieldSet;
 @class GPBUnknownFields;
 
diff --git a/objectivec/GPBUnknownFieldSet.h b/objectivec/GPBUnknownFieldSet.h
index cb64ae13fe..7807ff0023 100644
--- a/objectivec/GPBUnknownFieldSet.h
+++ b/objectivec/GPBUnknownFieldSet.h
@@ -7,6 +7,8 @@
 
 #import <Foundation/Foundation.h>
 
+#import "GPBUnknownField.h"
+
 @class GPBUnknownField;
 
 NS_ASSUME_NONNULL_BEGIN
diff --git a/objectivec/GPBUnknownFieldSet_PackagePrivate.h b/objectivec/GPBUnknownFieldSet_PackagePrivate.h
index 1d5ff50f45..0428fbb9b3 100644
--- a/objectivec/GPBUnknownFieldSet_PackagePrivate.h
+++ b/objectivec/GPBUnknownFieldSet_PackagePrivate.h
@@ -7,11 +7,10 @@
 
 #import <Foundation/Foundation.h>
 
+#import "GPBCodedInputStream.h"
+#import "GPBCodedOutputStream.h"
 #import "GPBUnknownFieldSet.h"
 
-@class GPBCodedOutputStream;
-@class GPBCodedInputStream;
-
 @interface GPBUnknownFieldSet ()
 
 - (NSData *)data;
diff --git a/objectivec/GPBUnknownField_PackagePrivate.h b/objectivec/GPBUnknownField_PackagePrivate.h
index dbcba75a4e..dde6548805 100644
--- a/objectivec/GPBUnknownField_PackagePrivate.h
+++ b/objectivec/GPBUnknownField_PackagePrivate.h
@@ -9,6 +9,8 @@
 
 #import "GPBUnknownField.h"
 
+#import "GPBArray.h"
+
 @class GPBCodedOutputStream;
 
 @interface GPBUnknownField () {
diff --git a/objectivec/GPBUnknownFields.h b/objectivec/GPBUnknownFields.h
index 859614b645..17ffc2def4 100644
--- a/objectivec/GPBUnknownFields.h
+++ b/objectivec/GPBUnknownFields.h
@@ -7,6 +7,9 @@
 
 #import <Foundation/Foundation.h>
 
+#import "GPBMessage.h"
+#import "GPBUnknownField.h"
+
 @class GPBMessage;
 @class GPBUnknownField;
 
diff --git a/objectivec/GPBUnknownFields_PackagePrivate.h b/objectivec/GPBUnknownFields_PackagePrivate.h
index ba2f251252..0d2fa7992f 100644
--- a/objectivec/GPBUnknownFields_PackagePrivate.h
+++ b/objectivec/GPBUnknownFields_PackagePrivate.h
@@ -9,8 +9,6 @@
 
 #import "GPBUnknownFields.h"
 
-@class GPBCodedOutputStream;
-
 @interface GPBUnknownFields ()
 
 - (nonnull NSData *)serializeAsData;
diff --git a/objectivec/GPBUtilities.h b/objectivec/GPBUtilities.h
index 578545df05..d317a3ba38 100644
--- a/objectivec/GPBUtilities.h
+++ b/objectivec/GPBUtilities.h
@@ -8,11 +8,10 @@
 #import <Foundation/Foundation.h>
 
 #import "GPBArray.h"
+#import "GPBDescriptor.h"
 #import "GPBMessage.h"
 #import "GPBRuntimeTypes.h"
 
-@class GPBOneofDescriptor;
-
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
diff --git a/objectivec/GPBUtilities_PackagePrivate.h b/objectivec/GPBUtilities_PackagePrivate.h
index b977f4ec32..e8c8cb52dc 100644
--- a/objectivec/GPBUtilities_PackagePrivate.h
+++ b/objectivec/GPBUtilities_PackagePrivate.h
@@ -9,6 +9,7 @@
 
 #import "GPBUtilities.h"
 
+#import "GPBDescriptor.h"
 #import "GPBDescriptor_PackagePrivate.h"
 
 // Macros for stringifying library symbols. These are used in the generated