diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2622a18d7c..8f62d7f847 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -60,7 +60,7 @@ set(AppleClang_min_version 14.0.3)
 set(MSVC_min_version 19.32)
 # Standard libraries
 set(libstdc++_min_version 12) # This should match GCC_min_version's major version.
-set(libc++_min_version 150000) # This should match Clang_min_version in the format "xxyyzz" instead of "xx.yy.zz" 
+set(libc++_min_version 150000) # This should match Clang_min_version in the format "xxyyzz" instead of "xx.yy.zz"
 
 dolphin_check_toolset_version("Xcode" XCODE_VERSION ${Xcode_min_version})
 dolphin_check_toolset_version("MSVC Toolset" MSVC_TOOLSET_VERSION ${MSVC_toolset_min_version})
@@ -273,6 +273,7 @@ if(MSVC)
 
   # Additional warnings
   add_compile_options(
+    /w15262 # Unannotated fallthrough between switch labels
     /w44263 # Non-virtual member function hides base class virtual function
     /w44265 # Class has virtual functions, but destructor is not virtual
     /w44946 # Reinterpret cast between related types
diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index 7871083785..5a65524555 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -45,6 +45,7 @@ else()
   check_and_add_flag(INIT_SELF -Winit-self)
   check_and_add_flag(MISSING_DECLARATIONS -Wmissing-declarations)
   check_and_add_flag(MISSING_VARIABLE_DECLARATIONS -Wmissing-variable-declarations)
+  check_and_add_flag(IMPLICIT_FALLTHROUGH -Wimplicit-fallthrough)
 
   # Disable -Wstringop-truncation warnings as they result in many false positives.
   # In most (all?) cases where std::strncpy is used, we want to fill the entire buffer
diff --git a/Source/Core/Common/GL/GLExtensions/GLExtensions.cpp b/Source/Core/Common/GL/GLExtensions/GLExtensions.cpp
index 3a724f3aba..f1453bca22 100644
--- a/Source/Core/Common/GL/GLExtensions/GLExtensions.cpp
+++ b/Source/Core/Common/GL/GLExtensions/GLExtensions.cpp
@@ -2157,8 +2157,10 @@ static void InitExtensionList(GLContext* context)
     default:
     case 320:
       s_extension_list["VERSION_GLES_3_2"] = true;
+      [[fallthrough]];
     case 310:
       s_extension_list["VERSION_GLES_3_1"] = true;
+      [[fallthrough]];
     case 300:
       s_extension_list["VERSION_GLES_3"] = true;
       break;
@@ -2195,6 +2197,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl450exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 440:
     {
@@ -2211,6 +2214,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl440exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 430:
     {
@@ -2239,6 +2243,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl430exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 420:
     {
@@ -2259,6 +2264,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl420exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 410:
     {
@@ -2273,6 +2279,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl410exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 400:
     {
@@ -2293,6 +2300,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl400exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 330:
     {
@@ -2311,6 +2319,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl330exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 320:
     {
@@ -2328,6 +2337,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl320exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 310:
     {
@@ -2343,6 +2353,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl310exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 300:
     {
@@ -2374,6 +2385,7 @@ static void InitExtensionList(GLContext* context)
       };
       for (auto it : gl300exts)
         s_extension_list[it] = true;
+      [[fallthrough]];
     }
     case 210:
     case 200:
diff --git a/Source/Core/Common/Hash.cpp b/Source/Core/Common/Hash.cpp
index 3756bdcad4..f5b9da1b20 100644
--- a/Source/Core/Common/Hash.cpp
+++ b/Source/Core/Common/Hash.cpp
@@ -136,33 +136,46 @@ static u64 GetMurmurHash3(const u8* src, u32 len, u32 samples)
   {
   case 15:
     k2 ^= u64(tail[14]) << 48;
+    [[fallthrough]];
   case 14:
     k2 ^= u64(tail[13]) << 40;
+    [[fallthrough]];
   case 13:
     k2 ^= u64(tail[12]) << 32;
+    [[fallthrough]];
   case 12:
     k2 ^= u64(tail[11]) << 24;
+    [[fallthrough]];
   case 11:
     k2 ^= u64(tail[10]) << 16;
+    [[fallthrough]];
   case 10:
     k2 ^= u64(tail[9]) << 8;
+    [[fallthrough]];
   case 9:
     k2 ^= u64(tail[8]) << 0;
-
+    [[fallthrough]];
   case 8:
     k1 ^= u64(tail[7]) << 56;
+    [[fallthrough]];
   case 7:
     k1 ^= u64(tail[6]) << 48;
+    [[fallthrough]];
   case 6:
     k1 ^= u64(tail[5]) << 40;
+    [[fallthrough]];
   case 5:
     k1 ^= u64(tail[4]) << 32;
+    [[fallthrough]];
   case 4:
     k1 ^= u64(tail[3]) << 24;
+    [[fallthrough]];
   case 3:
     k1 ^= u64(tail[2]) << 16;
+    [[fallthrough]];
   case 2:
     k1 ^= u64(tail[1]) << 8;
+    [[fallthrough]];
   case 1:
     k1 ^= u64(tail[0]) << 0;
     bmix64(h1, h2, k1, k2, c1, c2);
diff --git a/Source/Core/Core/HW/MagCard/MagneticCardReader.cpp b/Source/Core/Core/HW/MagCard/MagneticCardReader.cpp
index 80013e3a29..db78b9ffdd 100644
--- a/Source/Core/Core/HW/MagCard/MagneticCardReader.cpp
+++ b/Source/Core/Core/HW/MagCard/MagneticCardReader.cpp
@@ -193,6 +193,7 @@ void MagneticCardReader::Command_33_ReadData()
 
       AppendRange(&m_command_payload, *track_data);
     }
+    break;
   }
   default:
     break;
diff --git a/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp b/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp
index 4a55024d6e..682d5553e7 100644
--- a/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp
+++ b/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp
@@ -146,6 +146,7 @@ std::optional<IPCReply> BluetoothRealDevice::IOCtlV(const IOCtlVRequest& request
     }
 
     ERROR_LOG_FMT(IOS_WIIMOTE, "IOCTLV_USBV0_INTRMSG: Unknown endpoint: 0x{:02x}", cmd->endpoint);
+    break;
   }
   default:
     ERROR_LOG_FMT(IOS_WIIMOTE, "IOCtlV: Unknown request: 0x{:08x}", request.request);
diff --git a/Source/Core/DolphinQt/Debugger/CodeViewWidget.cpp b/Source/Core/DolphinQt/Debugger/CodeViewWidget.cpp
index c7a74ee29d..82d1473ee4 100644
--- a/Source/Core/DolphinQt/Debugger/CodeViewWidget.cpp
+++ b/Source/Core/DolphinQt/Debugger/CodeViewWidget.cpp
@@ -1174,7 +1174,9 @@ void CodeViewWidget::keyPressEvent(QKeyEvent* event)
     if (event->modifiers() == Qt::ControlModifier)
     {
       emit ActivateSearch();
+      return;
     }
+    [[fallthrough]];
   default:
     QWidget::keyPressEvent(event);
     break;
diff --git a/Source/Core/DolphinQt/Debugger/MemoryViewWidget.cpp b/Source/Core/DolphinQt/Debugger/MemoryViewWidget.cpp
index a5f5ef6eea..09740fa6b5 100644
--- a/Source/Core/DolphinQt/Debugger/MemoryViewWidget.cpp
+++ b/Source/Core/DolphinQt/Debugger/MemoryViewWidget.cpp
@@ -126,7 +126,9 @@ public:
       if (event->modifiers() == Qt::ControlModifier)
       {
         m_view->TriggerActivateSearch();
+        return;
       }
+      [[fallthrough]];
     default:
       QWidget::keyPressEvent(event);
       return;
@@ -356,6 +358,7 @@ void MemoryViewWidget::UpdateDispatcher(UpdateType type)
     // Values were captured on CPU thread while doing a callback.
     if (m_values.size() != 0)
       UpdateColumns();
+    break;
   default:
     break;
   }