diff --git a/Kernel/Arch/x86/Processor.h b/Kernel/Arch/x86/Processor.h
index 5d35c546de..857d3e8462 100644
--- a/Kernel/Arch/x86/Processor.h
+++ b/Kernel/Arch/x86/Processor.h
@@ -16,22 +16,20 @@
 #include <Kernel/Arch/x86/DescriptorTable.h>
 #include <Kernel/Arch/x86/PageDirectory.h>
 #include <Kernel/Arch/x86/TSS.h>
+#include <Kernel/Forward.h>
 
 namespace Kernel {
 
+class ProcessorInfo;
+class SchedulerPerProcessorData;
+struct MemoryManagerData;
+struct ProcessorMessageEntry;
+
 #if ARCH(X86_64)
 #    define MSR_FS_BASE 0xc0000100
 #    define MSR_GS_BASE 0xc0000101
 #endif
 
-class Thread;
-class SchedulerPerProcessorData;
-struct MemoryManagerData;
-struct ProcessorMessageEntry;
-
-struct TrapFrame;
-class ProcessorInfo;
-
 // FIXME: Find a better place for these
 extern "C" void thread_context_first_enter(void);
 extern "C" void exit_kernel_thread(void);
diff --git a/Kernel/CoreDump.h b/Kernel/CoreDump.h
index 76b4ab111b..1bbb98bf45 100644
--- a/Kernel/CoreDump.h
+++ b/Kernel/CoreDump.h
@@ -13,8 +13,6 @@
 
 namespace Kernel {
 
-class Process;
-
 class CoreDump {
 public:
     static OwnPtr<CoreDump> create(NonnullRefPtr<Process>, const String& output_path);
diff --git a/Kernel/FileSystem/DevFS.h b/Kernel/FileSystem/DevFS.h
index 785aa75f96..b962998c6d 100644
--- a/Kernel/FileSystem/DevFS.h
+++ b/Kernel/FileSystem/DevFS.h
@@ -14,13 +14,6 @@
 
 namespace Kernel {
 
-class DevFSInode;
-class DevFSDeviceInode;
-class DevFSDirectoryInode;
-class DevFSRootDirectoryInode;
-class DevFSDevicesDirectoryInode;
-class DevFSPtsDirectoryInode;
-class Device;
 class DevFS final : public FileSystem {
     friend class DevFSInode;
     friend class DevFSRootDirectoryInode;
diff --git a/Kernel/FileSystem/FileSystem.h b/Kernel/FileSystem/FileSystem.h
index 2e39a35236..d440e4cfe9 100644
--- a/Kernel/FileSystem/FileSystem.h
+++ b/Kernel/FileSystem/FileSystem.h
@@ -10,6 +10,7 @@
 #include <AK/RefPtr.h>
 #include <AK/StringView.h>
 #include <Kernel/FileSystem/InodeIdentifier.h>
+#include <Kernel/Forward.h>
 #include <Kernel/KResult.h>
 #include <Kernel/Lock.h>
 #include <Kernel/UnixTypes.h>
@@ -19,11 +20,6 @@ namespace Kernel {
 
 static constexpr u32 mepoch = 476763780;
 
-class Inode;
-class FileDescription;
-class LocalSocket;
-class VMObject;
-
 class FileSystem : public RefCounted<FileSystem> {
     friend class Inode;
 
diff --git a/Kernel/FileSystem/Forward.h b/Kernel/FileSystem/Forward.h
deleted file mode 100644
index 859af7747e..0000000000
--- a/Kernel/FileSystem/Forward.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-namespace Kernel {
-
-class FileSystem;
-class Inode;
-class Mount;
-class SysFS;
-class SysFSDirectoryInode;
-class SysFSInode;
-class VirtualFileSystem;
-struct InodeMetadata;
-
-}
diff --git a/Kernel/FileSystem/InodeWatcher.h b/Kernel/FileSystem/InodeWatcher.h
index 01c0fa3528..3425554e95 100644
--- a/Kernel/FileSystem/InodeWatcher.h
+++ b/Kernel/FileSystem/InodeWatcher.h
@@ -14,11 +14,10 @@
 #include <AK/NonnullOwnPtr.h>
 #include <Kernel/API/InodeWatcherEvent.h>
 #include <Kernel/FileSystem/File.h>
+#include <Kernel/Forward.h>
 
 namespace Kernel {
 
-class Inode;
-
 // A specific description of a watch.
 struct WatchDescription {
     int wd;
diff --git a/Kernel/FileSystem/Mount.h b/Kernel/FileSystem/Mount.h
index 44397744cc..e4a8782971 100644
--- a/Kernel/FileSystem/Mount.h
+++ b/Kernel/FileSystem/Mount.h
@@ -7,7 +7,7 @@
 #pragma once
 
 #include <AK/NonnullRefPtr.h>
-#include <Kernel/FileSystem/Forward.h>
+#include <Kernel/Forward.h>
 
 namespace Kernel {
 
diff --git a/Kernel/FileSystem/ProcFS.h b/Kernel/FileSystem/ProcFS.h
index d0cc2ffc41..fb9b4a7ead 100644
--- a/Kernel/FileSystem/ProcFS.h
+++ b/Kernel/FileSystem/ProcFS.h
@@ -10,17 +10,13 @@
 #include <AK/Types.h>
 #include <Kernel/FileSystem/FileSystem.h>
 #include <Kernel/FileSystem/Inode.h>
+#include <Kernel/Forward.h>
 #include <Kernel/KBufferBuilder.h>
 #include <Kernel/Lock.h>
 #include <Kernel/ProcessExposed.h>
 
 namespace Kernel {
 
-class Process;
-
-class ProcFSInode;
-class ProcFSDirectoryInode;
-
 class ProcFS final : public FileSystem {
     friend class ProcFSInode;
     friend class ProcFSDirectoryInode;
@@ -99,4 +95,5 @@ protected:
 
     ProcFS& m_parent_fs;
 };
+
 }
diff --git a/Kernel/FileSystem/SysFSComponent.h b/Kernel/FileSystem/SysFSComponent.h
index 7ed8d4d1bc..b645f86671 100644
--- a/Kernel/FileSystem/SysFSComponent.h
+++ b/Kernel/FileSystem/SysFSComponent.h
@@ -13,7 +13,7 @@
 #include <AK/Types.h>
 #include <Kernel/FileSystem/File.h>
 #include <Kernel/FileSystem/FileSystem.h>
-#include <Kernel/FileSystem/Forward.h>
+#include <Kernel/Forward.h>
 #include <Kernel/KResult.h>
 
 namespace Kernel {
diff --git a/Kernel/FileSystem/VirtualFileSystem.h b/Kernel/FileSystem/VirtualFileSystem.h
index c0820cc9ea..7e99b51fca 100644
--- a/Kernel/FileSystem/VirtualFileSystem.h
+++ b/Kernel/FileSystem/VirtualFileSystem.h
@@ -17,15 +17,12 @@
 #include <Kernel/FileSystem/InodeIdentifier.h>
 #include <Kernel/FileSystem/InodeMetadata.h>
 #include <Kernel/FileSystem/Mount.h>
+#include <Kernel/Forward.h>
 #include <Kernel/KResult.h>
 #include <Kernel/UnveilNode.h>
 
 namespace Kernel {
 
-class Custody;
-class Device;
-class FileDescription;
-
 struct UidAndGid {
     uid_t uid;
     gid_t gid;
diff --git a/Kernel/Forward.h b/Kernel/Forward.h
index abe758997c..08188be682 100644
--- a/Kernel/Forward.h
+++ b/Kernel/Forward.h
@@ -12,16 +12,23 @@ class BlockDevice;
 class CharacterDevice;
 class CoreDump;
 class Custody;
+class DevFSDeviceInode;
+class DevFSDirectoryInode;
+class DevFSInode;
+class DevFSPtsDirectoryInode;
+class DevFSRootDirectoryInode;
+class Device;
 class Device;
 class DiskCache;
 class DoubleBuffer;
 class File;
 class FileDescription;
+class FileSystem;
 class FutexQueue;
 class IPv4Socket;
 class Inode;
+class Inode;
 class InodeIdentifier;
-class SharedInodeVMObject;
 class InodeWatcher;
 class KBuffer;
 class KResult;
@@ -29,36 +36,55 @@ class LocalSocket;
 class Lock;
 class MappedROM;
 class MasterPTY;
+class Mount;
 class PageDirectory;
 class PerformanceEventBuffer;
 class PhysicalPage;
 class PhysicalRegion;
+class ProcFS;
+class ProcFSBusDirectory;
+class ProcFSDirectoryInode;
+class ProcFSExposedComponent;
+class ProcFSExposedDirectory;
+class ProcFSInode;
+class ProcFSProcessInformation;
+class ProcFSRootDirectory;
+class ProcFSSystemBoolean;
+class ProcFSSystemDirectory;
 class Process;
 class ProcessGroup;
-class ThreadTracer;
 class Range;
 class RangeAllocator;
+class RecursiveSpinLock;
 class Region;
 class Scheduler;
 class SchedulerPerProcessorData;
+class SharedInodeVMObject;
 class Socket;
 class Space;
-template<typename BaseType>
-class SpinLock;
-class RecursiveSpinLock;
-template<typename LockType>
-class ScopedSpinLock;
+class SysFS;
+class SysFSDirectoryInode;
+class SysFSInode;
 class TCPSocket;
 class TTY;
 class Thread;
+class ThreadTracer;
 class UDPSocket;
 class UserOrKernelBuffer;
-class VirtualFileSystem;
 class VMObject;
+class VirtualFileSystem;
+class VirtualFileSystem;
 class WaitQueue;
 class WorkQueue;
 
+template<typename BaseType>
+class SpinLock;
+template<typename LockType>
+class ScopedSpinLock;
 template<typename T>
 class KResultOr;
 
+struct InodeMetadata;
+struct TrapFrame;
+
 }
diff --git a/Kernel/GlobalProcessExposed.cpp b/Kernel/GlobalProcessExposed.cpp
index bd58e60610..22a03830c2 100644
--- a/Kernel/GlobalProcessExposed.cpp
+++ b/Kernel/GlobalProcessExposed.cpp
@@ -231,8 +231,6 @@ UNMAP_AFTER_INIT ProcFSNetworkDirectory::ProcFSNetworkDirectory(const ProcFSRoot
 {
 }
 
-class ProcFSSystemDirectory;
-
 class ProcFSDumpKmallocStacks : public ProcFSSystemBoolean {
 public:
     static NonnullRefPtr<ProcFSDumpKmallocStacks> must_create(const ProcFSSystemDirectory&);
diff --git a/Kernel/ProcessExposed.h b/Kernel/ProcessExposed.h
index 6401eabb31..2c739978e6 100644
--- a/Kernel/ProcessExposed.h
+++ b/Kernel/ProcessExposed.h
@@ -21,13 +21,6 @@
 
 namespace Kernel {
 
-class ProcFS;
-class ProcFSExposedComponent;
-class ProcFSExposedDirectory;
-class ProcFSRootDirectory;
-class ProcFSBusDirectory;
-class ProcFSSystemBoolean;
-
 class ProcFSComponentRegistry {
 public:
     static ProcFSComponentRegistry& the();
@@ -130,9 +123,6 @@ protected:
     mutable Lock m_lock { "ProcFSLink" };
 };
 
-class ProcFSRootDirectory;
-class ProcFSProcessInformation;
-
 class ProcFSProcessDirectory final
     : public ProcFSExposedDirectory {
     friend class ProcFSComponentRegistry;
@@ -167,8 +157,6 @@ private:
     NonnullRefPtr<Process> m_associated_process;
 };
 
-class ProcFSRootDirectory;
-
 class ProcFSBusDirectory : public ProcFSExposedDirectory {
     friend class ProcFSComponentRegistry;
 
diff --git a/Kernel/Scheduler.h b/Kernel/Scheduler.h
index 18dcd35cac..26d9adeecb 100644
--- a/Kernel/Scheduler.h
+++ b/Kernel/Scheduler.h
@@ -10,15 +10,13 @@
 #include <AK/Function.h>
 #include <AK/IntrusiveList.h>
 #include <AK/Types.h>
+#include <Kernel/Forward.h>
 #include <Kernel/SpinLock.h>
 #include <Kernel/Time/TimeManagement.h>
 #include <Kernel/UnixTypes.h>
 
 namespace Kernel {
 
-class Process;
-class Thread;
-class WaitQueue;
 struct RegisterState;
 
 extern Thread* g_finalizer;
diff --git a/Kernel/VM/MemoryManager.h b/Kernel/VM/MemoryManager.h
index 03a5b29fa8..d944a196b9 100644
--- a/Kernel/VM/MemoryManager.h
+++ b/Kernel/VM/MemoryManager.h
@@ -11,6 +11,7 @@
 #include <AK/NonnullRefPtrVector.h>
 #include <AK/String.h>
 #include <Kernel/Arch/x86/PageFault.h>
+#include <Kernel/Arch/x86/TrapFrame.h>
 #include <Kernel/Forward.h>
 #include <Kernel/SpinLock.h>
 #include <Kernel/VM/AllocationStrategy.h>
diff --git a/Kernel/VM/PageDirectory.h b/Kernel/VM/PageDirectory.h
index 6c02c03e12..2545f603cc 100644
--- a/Kernel/VM/PageDirectory.h
+++ b/Kernel/VM/PageDirectory.h
@@ -9,13 +9,12 @@
 #include <AK/HashMap.h>
 #include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
+#include <Kernel/Forward.h>
 #include <Kernel/VM/PhysicalPage.h>
 #include <Kernel/VM/RangeAllocator.h>
 
 namespace Kernel {
 
-class Process;
-
 class PageDirectory : public RefCounted<PageDirectory> {
     friend class MemoryManager;
 
diff --git a/Kernel/VM/Region.h b/Kernel/VM/Region.h
index 7fe7612a10..ed7bc9aff9 100644
--- a/Kernel/VM/Region.h
+++ b/Kernel/VM/Region.h
@@ -11,6 +11,7 @@
 #include <AK/WeakPtr.h>
 #include <AK/Weakable.h>
 #include <Kernel/Arch/x86/PageFault.h>
+#include <Kernel/Forward.h>
 #include <Kernel/Heap/SlabAllocator.h>
 #include <Kernel/KString.h>
 #include <Kernel/Sections.h>
@@ -21,9 +22,6 @@
 
 namespace Kernel {
 
-class Inode;
-class VMObject;
-
 enum class ShouldFlushTLB {
     No,
     Yes,
diff --git a/Kernel/VM/VMObject.h b/Kernel/VM/VMObject.h
index 64de251ef6..3c9cfbb831 100644
--- a/Kernel/VM/VMObject.h
+++ b/Kernel/VM/VMObject.h
@@ -12,13 +12,11 @@
 #include <AK/RefPtr.h>
 #include <AK/Vector.h>
 #include <AK/Weakable.h>
+#include <Kernel/Forward.h>
 #include <Kernel/Lock.h>
 
 namespace Kernel {
 
-class Inode;
-class PhysicalPage;
-
 class VMObjectDeletedHandler {
 public:
     virtual ~VMObjectDeletedHandler() = default;