diff --git a/Source/Core/AudioCommon/CubebStream.cpp b/Source/Core/AudioCommon/CubebStream.cpp
index adc947b426..0cdf7f3b99 100644
--- a/Source/Core/AudioCommon/CubebStream.cpp
+++ b/Source/Core/AudioCommon/CubebStream.cpp
@@ -12,7 +12,7 @@
 #include "Core/System.h"
 
 #ifdef _WIN32
-#include <Objbase.h>
+#include <objbase.h>
 #endif
 
 // ~10 ms - needs to be at least 240 for surround
diff --git a/Source/Core/AudioCommon/CubebUtils.cpp b/Source/Core/AudioCommon/CubebUtils.cpp
index 85fb44767e..0be4fdeb81 100644
--- a/Source/Core/AudioCommon/CubebUtils.cpp
+++ b/Source/Core/AudioCommon/CubebUtils.cpp
@@ -14,7 +14,7 @@
 #include <cubeb/cubeb.h>
 
 #ifdef _WIN32
-#include <Objbase.h>
+#include <objbase.h>
 #endif
 
 static void LogCallback(const char* format, ...)
diff --git a/Source/Core/AudioCommon/WASAPIStream.cpp b/Source/Core/AudioCommon/WASAPIStream.cpp
index 07a399a890..174ffbc9cb 100644
--- a/Source/Core/AudioCommon/WASAPIStream.cpp
+++ b/Source/Core/AudioCommon/WASAPIStream.cpp
@@ -7,7 +7,7 @@
 
 // clang-format off
 #include <initguid.h>
-#include <Audioclient.h>
+#include <audioclient.h>
 #include <mmdeviceapi.h>
 #include <functiondiscoverykeys_devpkey.h>
 #include <wil/resource.h>
diff --git a/Source/Core/AudioCommon/WASAPIStream.h b/Source/Core/AudioCommon/WASAPIStream.h
index dfe0974a8c..ba058c78d3 100644
--- a/Source/Core/AudioCommon/WASAPIStream.h
+++ b/Source/Core/AudioCommon/WASAPIStream.h
@@ -6,7 +6,7 @@
 #ifdef _WIN32
 
 // clang-format off
-#include <Windows.h>
+#include <windows.h>
 #include <mmreg.h>
 #include <objbase.h>
 #include <wil/resource.h>
diff --git a/Source/Core/Common/Arm64Emitter.cpp b/Source/Core/Common/Arm64Emitter.cpp
index cdb0b7e625..51c9823d17 100644
--- a/Source/Core/Common/Arm64Emitter.cpp
+++ b/Source/Core/Common/Arm64Emitter.cpp
@@ -21,7 +21,7 @@
 #include "Common/SmallVector.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 #ifdef __APPLE__
 #include <libkern/OSCacheControl.h>
diff --git a/Source/Core/Common/ArmCPUDetect.cpp b/Source/Core/Common/ArmCPUDetect.cpp
index 68a29caa45..91b66f807f 100644
--- a/Source/Core/Common/ArmCPUDetect.cpp
+++ b/Source/Core/Common/ArmCPUDetect.cpp
@@ -12,7 +12,7 @@
 #ifdef __APPLE__
 #include <sys/sysctl.h>
 #elif defined(_WIN32)
-#include <Windows.h>
+#include <windows.h>
 #include <arm64intr.h>
 #include "Common/WindowsRegistry.h"
 #elif defined(__linux__)
diff --git a/Source/Core/Common/CommonFuncs.cpp b/Source/Core/Common/CommonFuncs.cpp
index 2c70ced6ca..369d09066e 100644
--- a/Source/Core/Common/CommonFuncs.cpp
+++ b/Source/Core/Common/CommonFuncs.cpp
@@ -9,7 +9,7 @@
 
 #ifdef _WIN32
 #include <windows.h>
-#include <SetupAPI.h>
+#include <setupapi.h>
 
 #define strerror_r(err, buf, len) strerror_s(buf, len, err)
 
diff --git a/Source/Core/Common/CompatPatches.cpp b/Source/Core/Common/CompatPatches.cpp
index 8697357883..91394e96c0 100644
--- a/Source/Core/Common/CompatPatches.cpp
+++ b/Source/Core/Common/CompatPatches.cpp
@@ -1,7 +1,7 @@
 // Copyright 2008 Dolphin Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-#include <Windows.h>
+#include <windows.h>
 #include <functional>
 #include <optional>
 #include <string>
diff --git a/Source/Core/Common/DynamicLibrary.cpp b/Source/Core/Common/DynamicLibrary.cpp
index e9686859d3..ca6c17be6d 100644
--- a/Source/Core/Common/DynamicLibrary.cpp
+++ b/Source/Core/Common/DynamicLibrary.cpp
@@ -8,7 +8,7 @@
 #include <fmt/format.h>
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #else
 #include <dlfcn.h>
 #endif
diff --git a/Source/Core/Common/FileSearch.cpp b/Source/Core/Common/FileSearch.cpp
index a90b385ad9..9aed3373ec 100644
--- a/Source/Core/Common/FileSearch.cpp
+++ b/Source/Core/Common/FileSearch.cpp
@@ -11,8 +11,8 @@
 #include "Common/Logging/Log.h"
 #include "Common/StringUtil.h"
 
-#ifdef _MSC_VER
-#include <Windows.h>
+#ifdef _WIN32
+#include <windows.h>
 #elifdef ANDROID
 #include "jni/AndroidCommon/AndroidCommon.h"
 #endif
diff --git a/Source/Core/Common/FileUtil.cpp b/Source/Core/Common/FileUtil.cpp
index 9f17a58675..10032a03c5 100644
--- a/Source/Core/Common/FileUtil.cpp
+++ b/Source/Core/Common/FileUtil.cpp
@@ -29,13 +29,13 @@
 #include "Common/StringUtil.h"
 
 #ifdef _WIN32
-#include <Windows.h>
-#include <Shlwapi.h>
+#include <windows.h>
 #include <commdlg.h>  // for GetSaveFileName
 #include <direct.h>   // getcwd
 #include <io.h>
 #include <objbase.h>  // guid stuff
 #include <shellapi.h>
+#include <shlwapi.h>
 #else
 #include <libgen.h>
 #include <stdlib.h>
diff --git a/Source/Core/Common/LdrWatcher.cpp b/Source/Core/Common/LdrWatcher.cpp
index a0db0b61c6..31a8278bba 100644
--- a/Source/Core/Common/LdrWatcher.cpp
+++ b/Source/Core/Common/LdrWatcher.cpp
@@ -3,9 +3,9 @@
 
 #include "Common/LdrWatcher.h"
 
-#include <Windows.h>
-#include <TlHelp32.h>
+#include <windows.h>
 #include <string>
+#include <tlhelp32.h>
 #include <winternl.h>
 
 typedef struct _LDR_DLL_LOADED_NOTIFICATION_DATA
diff --git a/Source/Core/Common/Network.cpp b/Source/Core/Common/Network.cpp
index 58994c635d..90dcd7017f 100644
--- a/Source/Core/Common/Network.cpp
+++ b/Source/Core/Common/Network.cpp
@@ -13,7 +13,7 @@
 #include <netinet/in.h>
 #include <sys/socket.h>
 #else
-#include <WinSock2.h>
+#include <winsock2.h>
 #endif
 
 #include <fmt/format.h>
diff --git a/Source/Core/Common/SocketContext.h b/Source/Core/Common/SocketContext.h
index 0aa4929e89..5dcf45df5d 100644
--- a/Source/Core/Common/SocketContext.h
+++ b/Source/Core/Common/SocketContext.h
@@ -4,8 +4,8 @@
 #pragma once
 
 #ifdef _WIN32
-#include <WinSock2.h>
 #include <mutex>
+#include <winsock2.h>
 #endif
 
 namespace Common
diff --git a/Source/Core/Common/StringUtil.cpp b/Source/Core/Common/StringUtil.cpp
index e84fabcbb5..6a498474e1 100644
--- a/Source/Core/Common/StringUtil.cpp
+++ b/Source/Core/Common/StringUtil.cpp
@@ -25,7 +25,7 @@
 #include "Common/Logging/Log.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #include <shellapi.h>
 constexpr u32 CODEPAGE_SHIFT_JIS = 932;
 constexpr u32 CODEPAGE_WINDOWS_1252 = 1252;
diff --git a/Source/Core/Common/Thread.cpp b/Source/Core/Common/Thread.cpp
index 258559bc4f..d9a40fc6b5 100644
--- a/Source/Core/Common/Thread.cpp
+++ b/Source/Core/Common/Thread.cpp
@@ -4,7 +4,7 @@
 #include "Common/Thread.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #include <processthreadsapi.h>
 #else
 #include <pthread.h>
diff --git a/Source/Core/Common/Timer.cpp b/Source/Core/Common/Timer.cpp
index 957073426b..fcbbd7bbd2 100644
--- a/Source/Core/Common/Timer.cpp
+++ b/Source/Core/Common/Timer.cpp
@@ -8,7 +8,7 @@
 #include "Common/CommonFuncs.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #include <timeapi.h>
 #endif
 
diff --git a/Source/Core/Common/WindowsDevice.cpp b/Source/Core/Common/WindowsDevice.cpp
index 34a540ed7b..dc7d4ad68c 100644
--- a/Source/Core/Common/WindowsDevice.cpp
+++ b/Source/Core/Common/WindowsDevice.cpp
@@ -7,7 +7,7 @@
 
 #include <string>
 
-#include "Hidclass.h"
+#include "hidclass.h"
 
 #include "Common/CommonFuncs.h"
 #include "Common/Logging/Log.h"
diff --git a/Source/Core/Common/WindowsDevice.h b/Source/Core/Common/WindowsDevice.h
index 78e8234c15..8de1b6b01f 100644
--- a/Source/Core/Common/WindowsDevice.h
+++ b/Source/Core/Common/WindowsDevice.h
@@ -16,11 +16,10 @@
 #ifndef NOMINMAX
 #define NOMINMAX
 #endif
-#include <Windows.h>
-
-#include <SetupAPI.h>
+#include <windows.h>
 #include <cfgmgr32.h>
 #include <devpropdef.h>
+#include <setupapi.h>
 
 #include "Common/Functional.h"
 
diff --git a/Source/Core/Common/WindowsRegistry.cpp b/Source/Core/Common/WindowsRegistry.cpp
index 6067420669..e95bd2da0c 100644
--- a/Source/Core/Common/WindowsRegistry.cpp
+++ b/Source/Core/Common/WindowsRegistry.cpp
@@ -1,6 +1,6 @@
 #include "Common/WindowsRegistry.h"
 
-#include <Windows.h>
+#include <windows.h>
 #include <string>
 #include <type_traits>
 #include "Common/StringUtil.h"
diff --git a/Source/Core/Common/WindowsRegistry.h b/Source/Core/Common/WindowsRegistry.h
index 7dc3a52f91..affeba41cb 100644
--- a/Source/Core/Common/WindowsRegistry.h
+++ b/Source/Core/Common/WindowsRegistry.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <Windows.h>
+#include <windows.h>
 #include <string>
 
 #include "Common/CommonTypes.h"
diff --git a/Source/Core/Core/Config/DefaultLocale.cpp b/Source/Core/Core/Config/DefaultLocale.cpp
index 79c4c67787..55f304c88f 100644
--- a/Source/Core/Core/Config/DefaultLocale.cpp
+++ b/Source/Core/Core/Config/DefaultLocale.cpp
@@ -11,7 +11,7 @@
 #include <vector>
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include "Common/Assert.h"
diff --git a/Source/Core/Core/DolphinAnalytics.cpp b/Source/Core/Core/DolphinAnalytics.cpp
index 936cd7191b..1fff6bc5c5 100644
--- a/Source/Core/Core/DolphinAnalytics.cpp
+++ b/Source/Core/Core/DolphinAnalytics.cpp
@@ -13,7 +13,7 @@
 #include <fmt/format.h>
 
 #if defined(_WIN32)
-#include <Windows.h>
+#include <windows.h>
 #include "Common/WindowsRegistry.h"
 #endif
 
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
index 61c55857b2..a2151f949b 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
@@ -4,7 +4,7 @@
 #include "Core/HW/DSPHLE/UCodes/ROM.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include "Common/ChunkFile.h"
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.cpp
index d6fd59b145..5bc1e2b1d0 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.cpp
@@ -7,7 +7,7 @@
 #include <memory>
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include "Common/ChunkFile.h"
diff --git a/Source/Core/Core/HW/EXI/BBA/BuiltIn.h b/Source/Core/Core/HW/EXI/BBA/BuiltIn.h
index 691431f1c8..d1f656de64 100644
--- a/Source/Core/Core/HW/EXI/BBA/BuiltIn.h
+++ b/Source/Core/Core/HW/EXI/BBA/BuiltIn.h
@@ -4,7 +4,7 @@
 #pragma once
 
 #ifdef _WIN32
-#include <WinSock2.h>
+#include <winsock2.h>
 using socklen_t = int;
 #else
 #include <netinet/in.h>
diff --git a/Source/Core/Core/HW/EXI/EXI_DeviceEthernet.h b/Source/Core/Core/HW/EXI/EXI_DeviceEthernet.h
index 00d0fcb84e..59fabfafd1 100644
--- a/Source/Core/Core/HW/EXI/EXI_DeviceEthernet.h
+++ b/Source/Core/Core/HW/EXI/EXI_DeviceEthernet.h
@@ -11,7 +11,7 @@
 #include "SFML/Network/IpAddress.hpp"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include <SFML/Network.hpp>
diff --git a/Source/Core/Core/HW/EXI/EXI_DeviceMic.cpp b/Source/Core/Core/HW/EXI/EXI_DeviceMic.cpp
index 2d3d66feab..714fdbf870 100644
--- a/Source/Core/Core/HW/EXI/EXI_DeviceMic.cpp
+++ b/Source/Core/Core/HW/EXI/EXI_DeviceMic.cpp
@@ -20,7 +20,7 @@
 #include "Core/System.h"
 
 #ifdef _WIN32
-#include <Objbase.h>
+#include <objbase.h>
 #endif
 
 namespace ExpansionInterface
diff --git a/Source/Core/Core/HW/WiimoteReal/IOWin.cpp b/Source/Core/Core/HW/WiimoteReal/IOWin.cpp
index b65bab19b5..b2e4a5cab0 100644
--- a/Source/Core/Core/HW/WiimoteReal/IOWin.cpp
+++ b/Source/Core/Core/HW/WiimoteReal/IOWin.cpp
@@ -9,11 +9,11 @@
 #include <optional>
 #include <vector>
 
-#include <Windows.h>
-#include <BluetoothAPIs.h>
-#include <Cfgmgr32.h>
-#include <Hidclass.h>
-#include <Hidsdi.h>
+#include <windows.h>
+#include <bluetoothapis.h>
+#include <cfgmgr32.h>
+#include <hidclass.h>
+#include <hidsdi.h>
 #include <initguid.h>
 #include <wtypes.h>
 // initguid.h must be included before devpkey.h
diff --git a/Source/Core/Core/IOS/FS/FileSystem.h b/Source/Core/Core/IOS/FS/FileSystem.h
index 8d9f5ebf64..cf9bf8c64b 100644
--- a/Source/Core/Core/IOS/FS/FileSystem.h
+++ b/Source/Core/Core/IOS/FS/FileSystem.h
@@ -12,7 +12,7 @@
 
 #ifdef _WIN32
 // TODO: Horrible hack, remove ASAP!
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include "Common/CommonTypes.h"
diff --git a/Source/Core/Core/IOS/Network/ICMP.h b/Source/Core/Core/IOS/Network/ICMP.h
index 258a9b6c3f..64131f02d3 100644
--- a/Source/Core/Core/IOS/Network/ICMP.h
+++ b/Source/Core/Core/IOS/Network/ICMP.h
@@ -4,7 +4,7 @@
 #pragma once
 
 #ifdef _WIN32
-#include <WinSock2.h>
+#include <winsock2.h>
 #else
 #include <netinet/in.h>
 #endif
diff --git a/Source/Core/Core/IOS/Network/Socket.h b/Source/Core/Core/IOS/Network/Socket.h
index 4f07612799..88a018dc9c 100644
--- a/Source/Core/Core/IOS/Network/Socket.h
+++ b/Source/Core/Core/IOS/Network/Socket.h
@@ -4,8 +4,8 @@
 #pragma once
 
 #ifdef _WIN32
-#include <WinSock2.h>
 #include <iphlpapi.h>
+#include <winsock2.h>
 #include <ws2tcpip.h>
 
 typedef pollfd pollfd_t;
diff --git a/Source/Core/Core/IOS/USB/Emulated/Microphone.cpp b/Source/Core/Core/IOS/USB/Emulated/Microphone.cpp
index db261eb076..fe0363c915 100644
--- a/Source/Core/Core/IOS/USB/Emulated/Microphone.cpp
+++ b/Source/Core/Core/IOS/USB/Emulated/Microphone.cpp
@@ -21,7 +21,7 @@
 #include "Core/System.h"
 
 #ifdef _WIN32
-#include <Objbase.h>
+#include <objbase.h>
 #endif
 
 #ifdef ANDROID
diff --git a/Source/Core/Core/NetworkCaptureLogger.h b/Source/Core/Core/NetworkCaptureLogger.h
index 27489ec089..1324171eef 100644
--- a/Source/Core/Core/NetworkCaptureLogger.h
+++ b/Source/Core/Core/NetworkCaptureLogger.h
@@ -9,7 +9,7 @@
 #include <mutex>
 
 #ifdef _WIN32
-#include <WinSock2.h>
+#include <winsock2.h>
 using socklen_t = int;
 #else
 #include <netinet/in.h>
diff --git a/Source/Core/Core/PowerPC/GDBStub.cpp b/Source/Core/Core/PowerPC/GDBStub.cpp
index 088a74c926..f8e6c51a14 100644
--- a/Source/Core/Core/PowerPC/GDBStub.cpp
+++ b/Source/Core/Core/PowerPC/GDBStub.cpp
@@ -9,8 +9,8 @@
 #include <optional>
 #include <string.h>
 #ifdef _WIN32
-#include <WinSock2.h>
 #include <iphlpapi.h>
+#include <winsock2.h>
 #include <ws2tcpip.h>
 typedef SSIZE_T ssize_t;
 #define SHUT_RDWR SD_BOTH
diff --git a/Source/Core/DolphinNoGUI/MainNoGUI.cpp b/Source/Core/DolphinNoGUI/MainNoGUI.cpp
index 1e1ff6e39f..3bf40ea0d4 100644
--- a/Source/Core/DolphinNoGUI/MainNoGUI.cpp
+++ b/Source/Core/DolphinNoGUI/MainNoGUI.cpp
@@ -12,7 +12,7 @@
 #ifndef _WIN32
 #include <unistd.h>
 #else
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include "Common/ScopeGuard.h"
diff --git a/Source/Core/DolphinNoGUI/PlatformWin32.cpp b/Source/Core/DolphinNoGUI/PlatformWin32.cpp
index ff07698115..90d337200c 100644
--- a/Source/Core/DolphinNoGUI/PlatformWin32.cpp
+++ b/Source/Core/DolphinNoGUI/PlatformWin32.cpp
@@ -8,7 +8,7 @@
 #include "Core/Core.h"
 #include "Core/System.h"
 
-#include <Windows.h>
+#include <windows.h>
 #include <climits>
 #include <dwmapi.h>
 
diff --git a/Source/Core/DolphinQt/Main.cpp b/Source/Core/DolphinQt/Main.cpp
index b223819e7a..6ebff53462 100644
--- a/Source/Core/DolphinQt/Main.cpp
+++ b/Source/Core/DolphinQt/Main.cpp
@@ -6,7 +6,7 @@
 #include <string>
 #include <vector>
 
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #ifdef __linux__
diff --git a/Source/Core/DolphinQt/RenderWidget.cpp b/Source/Core/DolphinQt/RenderWidget.cpp
index 9b5026d5fb..49680b8482 100644
--- a/Source/Core/DolphinQt/RenderWidget.cpp
+++ b/Source/Core/DolphinQt/RenderWidget.cpp
@@ -32,7 +32,7 @@
 #include "VideoCommon/Present.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #include <dwmapi.h>
 #endif
 
diff --git a/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.cpp b/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.cpp
index 4379749e5f..3d3d8049c0 100644
--- a/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.cpp
@@ -7,8 +7,8 @@
 #include <unordered_set>
 #include <vector>
 
-#include <Windows.h>
-#include <SetupAPI.h>
+#include <windows.h>
+#include <setupapi.h>
 
 namespace ciface::DInput
 {
diff --git a/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.h b/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.h
index de3d684372..52911dabaa 100644
--- a/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.h
+++ b/Source/Core/InputCommon/ControllerInterface/DInput/XInputFilter.h
@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include <Windows.h>
+#include <windows.h>
 #include <unordered_set>
 
 namespace ciface::DInput
diff --git a/Source/Core/InputCommon/ControllerInterface/ForceFeedback/ForceFeedbackDevice.h b/Source/Core/InputCommon/ControllerInterface/ForceFeedback/ForceFeedbackDevice.h
index 6a00d2812a..dabc1d5c63 100644
--- a/Source/Core/InputCommon/ControllerInterface/ForceFeedback/ForceFeedbackDevice.h
+++ b/Source/Core/InputCommon/ControllerInterface/ForceFeedback/ForceFeedbackDevice.h
@@ -7,7 +7,7 @@
 #include <string>
 #include <thread>
 
-#include <Windows.h>
+#include <windows.h>
 
 #include "Common/Event.h"
 #include "Common/Flag.h"
diff --git a/Source/Core/InputCommon/ControllerInterface/SDL/SDL.cpp b/Source/Core/InputCommon/ControllerInterface/SDL/SDL.cpp
index f6912f67ce..5aeb9e07db 100644
--- a/Source/Core/InputCommon/ControllerInterface/SDL/SDL.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/SDL/SDL.cpp
@@ -8,7 +8,7 @@
 #include <vector>
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include <SDL3/SDL.h>
diff --git a/Source/Core/InputCommon/ControllerInterface/Win32/Win32.cpp b/Source/Core/InputCommon/ControllerInterface/Win32/Win32.cpp
index 79584913cf..eb4bd6fd6b 100644
--- a/Source/Core/InputCommon/ControllerInterface/Win32/Win32.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/Win32/Win32.cpp
@@ -3,7 +3,7 @@
 
 #include "InputCommon/ControllerInterface/Win32/Win32.h"
 
-#include <Windows.h>
+#include <windows.h>
 #include <cfgmgr32.h>
 // must be before hidclass
 #include <initguid.h>
diff --git a/Source/Core/InputCommon/ControllerInterface/XInput/XInput.h b/Source/Core/InputCommon/ControllerInterface/XInput/XInput.h
index 95fe6a3c6f..b006d1c7cc 100644
--- a/Source/Core/InputCommon/ControllerInterface/XInput/XInput.h
+++ b/Source/Core/InputCommon/ControllerInterface/XInput/XInput.h
@@ -9,7 +9,7 @@
 #pragma once
 
 #include <windows.h>
-#include <XInput.h>
+#include <xinput.h>
 
 #include "InputCommon/ControllerInterface/ControllerInterface.h"
 
diff --git a/Source/Core/UICommon/AutoUpdate.cpp b/Source/Core/UICommon/AutoUpdate.cpp
index 4298382b32..f90f4d5ff8 100644
--- a/Source/Core/UICommon/AutoUpdate.cpp
+++ b/Source/Core/UICommon/AutoUpdate.cpp
@@ -18,7 +18,7 @@
 #include "Common/Version.h"
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #else
 #include <unistd.h>
 #endif
diff --git a/Source/Core/UpdaterCommon/UpdaterCommon.cpp b/Source/Core/UpdaterCommon/UpdaterCommon.cpp
index 0d98f19187..8a400b21d0 100644
--- a/Source/Core/UpdaterCommon/UpdaterCommon.cpp
+++ b/Source/Core/UpdaterCommon/UpdaterCommon.cpp
@@ -32,7 +32,7 @@
 #endif
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #include <filesystem>
 #endif
 
diff --git a/Source/Core/WinUpdater/Platform.cpp b/Source/Core/WinUpdater/Platform.cpp
index c48271be55..8e6d0eaf6f 100644
--- a/Source/Core/WinUpdater/Platform.cpp
+++ b/Source/Core/WinUpdater/Platform.cpp
@@ -1,4 +1,4 @@
-#include <Windows.h>
+#include <windows.h>
 
 #include <filesystem>
 #include <map>
diff --git a/Source/Core/WinUpdater/WinUI.cpp b/Source/Core/WinUpdater/WinUI.cpp
index c6e65626e9..0a92172911 100644
--- a/Source/Core/WinUpdater/WinUI.cpp
+++ b/Source/Core/WinUpdater/WinUI.cpp
@@ -7,11 +7,11 @@
 #include <string>
 #include <thread>
 
-#include <Windows.h>
-#include <CommCtrl.h>
-#include <ShObjIdl.h>
-#include <ShlObj.h>
+#include <windows.h>
+#include <commctrl.h>
 #include <shellapi.h>
+#include <shlobj.h>
+#include <shobjidl.h>
 #include <wrl/client.h>
 
 #include "Common/Event.h"
diff --git a/Source/PCH/pch.h b/Source/PCH/pch.h
index 484f2d343b..e132288548 100644
--- a/Source/PCH/pch.h
+++ b/Source/PCH/pch.h
@@ -94,7 +94,7 @@
 #include <vector>
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 #include "Common/Common.h"