diff --git a/Source/Core/Common/MemoryUtil.cpp b/Source/Core/Common/MemoryUtil.cpp
index f94af858222f..b473705411be 100644
--- a/Source/Core/Common/MemoryUtil.cpp
+++ b/Source/Core/Common/MemoryUtil.cpp
@@ -250,7 +250,7 @@ size_t MemPhysical()
   mib[1] = HW_PHYSMEM64;
 #endif
   size_t length = sizeof(size_t);
-  sysctl(mib, 2, &physical_memory, &length, NULL, 0);
+  sysctl(mib, 2, &physical_memory, &length, nullptr, 0);
   return physical_memory;
 #elif defined __HAIKU__
   system_info sysinfo;
diff --git a/Source/Core/DolphinNoGUI/PlatformWin32.cpp b/Source/Core/DolphinNoGUI/PlatformWin32.cpp
index a34ace70ce18..4b5e5aa1ef88 100644
--- a/Source/Core/DolphinNoGUI/PlatformWin32.cpp
+++ b/Source/Core/DolphinNoGUI/PlatformWin32.cpp
@@ -62,12 +62,12 @@ bool PlatformWin32::RegisterRenderWindowClass()
   wc.cbClsExtra = 0;
   wc.cbWndExtra = 0;
   wc.hInstance = GetModuleHandle(nullptr);
-  wc.hIcon = LoadIcon(NULL, IDI_ICON1);
-  wc.hCursor = LoadCursor(NULL, IDC_ARROW);
+  wc.hIcon = LoadIcon(nullptr, IDI_ICON1);
+  wc.hCursor = LoadCursor(nullptr, IDC_ARROW);
   wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
-  wc.lpszMenuName = NULL;
+  wc.lpszMenuName = nullptr;
   wc.lpszClassName = WINDOW_CLASS_NAME;
-  wc.hIconSm = LoadIcon(NULL, IDI_ICON1);
+  wc.hIconSm = LoadIcon(nullptr, IDI_ICON1);
 
   if (!RegisterClassEx(&wc))
   {
diff --git a/Source/Core/DolphinQt/QtUtils/WinIconHelper.cpp b/Source/Core/DolphinQt/QtUtils/WinIconHelper.cpp
index f1c39a4c09be..7dc558371b99 100644
--- a/Source/Core/DolphinQt/QtUtils/WinIconHelper.cpp
+++ b/Source/Core/DolphinQt/QtUtils/WinIconHelper.cpp
@@ -42,7 +42,7 @@ static QPixmap PixmapFromHICON(HICON icon)
   const int h = iconinfo.yHotspot * 2;
   BITMAPINFO bitmapInfo = GetBMI(w, h, false);
   DWORD* bits;
-  HBITMAP winBitmap = CreateDIBSection(hdc, &bitmapInfo, DIB_RGB_COLORS, (VOID**)&bits, NULL, 0);
+  HBITMAP winBitmap = CreateDIBSection(hdc, &bitmapInfo, DIB_RGB_COLORS, (VOID**)&bits, nullptr, 0);
   HGDIOBJ oldhdc = reinterpret_cast<HBITMAP>(SelectObject(hdc, winBitmap));
   DrawIconEx(hdc, 0, 0, icon, iconinfo.xHotspot * 2, iconinfo.yHotspot * 2, 0, 0, DI_NORMAL);
 
diff --git a/Source/Core/VideoBackends/D3D12/DX12Context.cpp b/Source/Core/VideoBackends/D3D12/DX12Context.cpp
index 8343e39a6ec2..19a13f64b4f3 100644
--- a/Source/Core/VideoBackends/D3D12/DX12Context.cpp
+++ b/Source/Core/VideoBackends/D3D12/DX12Context.cpp
@@ -221,7 +221,7 @@ bool DXContext::CreateFence()
     return false;
 
   m_fence_event = CreateEvent(nullptr, FALSE, FALSE, nullptr);
-  ASSERT_MSG(VIDEO, m_fence_event != NULL, "Failed to create fence event");
+  ASSERT_MSG(VIDEO, m_fence_event != nullptr, "Failed to create fence event");
   if (!m_fence_event)
     return false;
 
diff --git a/Source/Core/WinUpdater/Main.cpp b/Source/Core/WinUpdater/Main.cpp
index 6b7fd801efd3..66fc5216712e 100644
--- a/Source/Core/WinUpdater/Main.cpp
+++ b/Source/Core/WinUpdater/Main.cpp
@@ -58,7 +58,7 @@ int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine
     }
 
     // Relaunch the updater as administrator
-    ShellExecuteW(nullptr, L"runas", path->c_str(), pCmdLine, NULL, SW_SHOW);
+    ShellExecuteW(nullptr, L"runas", path->c_str(), pCmdLine, nullptr, SW_SHOW);
     return 0;
   }
 
diff --git a/Source/Core/WinUpdater/WinUI.cpp b/Source/Core/WinUpdater/WinUI.cpp
index 418764813b82..696ac55b0a15 100644
--- a/Source/Core/WinUpdater/WinUI.cpp
+++ b/Source/Core/WinUpdater/WinUI.cpp
@@ -77,7 +77,7 @@ bool InitWindow()
   if (!window_handle)
     return false;
 
-  if (SUCCEEDED(CoCreateInstance(CLSID_TaskbarList, NULL, CLSCTX_INPROC_SERVER,
+  if (SUCCEEDED(CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_INPROC_SERVER,
                                  IID_PPV_ARGS(taskbar_list.GetAddressOf()))))
   {
     if (FAILED(taskbar_list->HrInit()))
@@ -88,8 +88,8 @@ bool InitWindow()
 
   int y = PADDING_HEIGHT;
 
-  label_handle = CreateWindow(L"STATIC", NULL, WS_VISIBLE | WS_CHILD, 5, y, 500, 25, window_handle,
-                              nullptr, nullptr, 0);
+  label_handle = CreateWindow(L"STATIC", nullptr, WS_VISIBLE | WS_CHILD, 5, y, 500, 25,
+                              window_handle, nullptr, nullptr, 0);
 
   if (!label_handle)
     return false;
@@ -106,7 +106,7 @@ bool InitWindow()
 
   y += GetWindowHeight(label_handle) + PADDING_HEIGHT;
 
-  total_progressbar_handle = CreateWindow(PROGRESS_CLASS, NULL, PROGRESSBAR_FLAGS, 5, y, 470, 25,
+  total_progressbar_handle = CreateWindow(PROGRESS_CLASS, nullptr, PROGRESSBAR_FLAGS, 5, y, 470, 25,
                                           window_handle, nullptr, nullptr, 0);
 
   y += GetWindowHeight(total_progressbar_handle) + PADDING_HEIGHT;
@@ -114,8 +114,8 @@ bool InitWindow()
   if (!total_progressbar_handle)
     return false;
 
-  current_progressbar_handle = CreateWindow(PROGRESS_CLASS, NULL, PROGRESSBAR_FLAGS, 5, y, 470, 25,
-                                            window_handle, nullptr, nullptr, 0);
+  current_progressbar_handle = CreateWindow(PROGRESS_CLASS, nullptr, PROGRESSBAR_FLAGS, 5, y, 470,
+                                            25, window_handle, nullptr, nullptr, 0);
 
   y += GetWindowHeight(current_progressbar_handle) + PADDING_HEIGHT;