diff --git a/cmake/compileroptions.cmake b/cmake/compileroptions.cmake
index 8f7b766e2..55656446b 100644
--- a/cmake/compileroptions.cmake
+++ b/cmake/compileroptions.cmake
@@ -51,6 +51,7 @@ elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
    add_compile_options_safe(-Wdocumentation)
    add_compile_options_safe(-Wdocumentation-pedantic)
    add_compile_options_safe(-Wno-documentation-unknown-command)
+   add_compile_options_safe(-Wimplicit-fallthrough)
 
    if(ENABLE_COVERAGE OR ENABLE_COVERAGE_XML)
       message(FATAL_ERROR "Do not use clang for generate code coverage. Use gcc.")
diff --git a/gui/projectfile.cpp b/gui/projectfile.cpp
index e3f986f7b..f6accf5ad 100644
--- a/gui/projectfile.cpp
+++ b/gui/projectfile.cpp
@@ -248,6 +248,7 @@ void ProjectFile::readBuildDir(QXmlStreamReader &reader)
         switch (type) {
         case QXmlStreamReader::Characters:
             mBuildDir = reader.text().toString();
+            FALLTHROUGH;
         case QXmlStreamReader::EndElement:
             return;
         // Not handled
@@ -273,6 +274,7 @@ void ProjectFile::readImportProject(QXmlStreamReader &reader)
         switch (type) {
         case QXmlStreamReader::Characters:
             mImportProject = reader.text().toString();
+            FALLTHROUGH;
         case QXmlStreamReader::EndElement:
             return;
         // Not handled
@@ -298,6 +300,7 @@ bool ProjectFile::readBool(QXmlStreamReader &reader)
         switch (type) {
         case QXmlStreamReader::Characters:
             ret = (reader.text().toString() == "true");
+            FALLTHROUGH;
         case QXmlStreamReader::EndElement:
             return ret;
         // Not handled
@@ -323,6 +326,7 @@ int ProjectFile::readInt(QXmlStreamReader &reader, int defaultValue)
         switch (type) {
         case QXmlStreamReader::Characters:
             ret = reader.text().toString().toInt();
+            FALLTHROUGH;
         case QXmlStreamReader::EndElement:
             return ret;
         // Not handled
@@ -617,6 +621,7 @@ void ProjectFile::readPlatform(QXmlStreamReader &reader)
         switch (type) {
         case QXmlStreamReader::Characters:
             mPlatform = reader.text().toString();
+            FALLTHROUGH;
         case QXmlStreamReader::EndElement:
             return;
         // Not handled
diff --git a/lib/analyzer.h b/lib/analyzer.h
index b2a1dad4d..502407a53 100644
--- a/lib/analyzer.h
+++ b/lib/analyzer.h
@@ -121,7 +121,7 @@ struct Analyzer {
     /// If the analysis is unsure whether to update a scope, this will return true if the analysis should bifurcate the scope
     virtual bool updateScope(const Token* endBlock, bool modified) const = 0;
     /// Called when a scope will be forked
-    virtual void forkScope(const Token* endBlock) {}
+    virtual void forkScope(const Token* /*endBlock*/) {}
     /// If the value is conditional
     virtual bool isConditional() const = 0;
     /// The condition that will be assumed during analysis
diff --git a/lib/checkio.cpp b/lib/checkio.cpp
index 2390d53d4..2f59b5edd 100644
--- a/lib/checkio.cpp
+++ b/lib/checkio.cpp
@@ -929,7 +929,7 @@ void CheckIO::checkFormatString(const Token * const tok,
                             case 'l':
                                 if (i+1 != formatString.end() && *(i+1) == *i)
                                     specifier += *i++;
-                            // fallthrough
+                                FALLTHROUGH;
                             case 'j':
                             case 'q':
                             case 't':
@@ -1255,7 +1255,7 @@ void CheckIO::checkFormatString(const Token * const tok,
                                     specifier += *i++;
                                     specifier += *i++;
                                 }
-                            // fallthrough
+                                FALLTHROUGH;
                             case 'j': // intmax_t or uintmax_t
                             case 'z': // size_t
                             case 't': // ptrdiff_t
diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
index f4bc4f8f2..69b94e815 100644
--- a/lib/checkstl.cpp
+++ b/lib/checkstl.cpp
@@ -1105,7 +1105,7 @@ void CheckStl::invalidContainerLoopError(const Token *tok, const Token * loopTok
     reportError(errorPath, Severity::error, "invalidContainerLoop", msg, CWE664, false);
 }
 
-void CheckStl::invalidContainerError(const Token *tok, const Token * contTok, const ValueFlow::Value *val, ErrorPath errorPath)
+void CheckStl::invalidContainerError(const Token *tok, const Token * /*contTok*/, const ValueFlow::Value *val, ErrorPath errorPath)
 {
     const bool inconclusive = val ? val->isInconclusive() : false;
     if (val)
diff --git a/lib/config.h b/lib/config.h
index 4bbb80359..c6034d6e6 100644
--- a/lib/config.h
+++ b/lib/config.h
@@ -46,6 +46,15 @@
 #  define NORETURN
 #endif
 
+// fallthrough
+#if defined(__clang__)
+#  define FALLTHROUGH [[clang::fallthrough]]
+#elif (defined(__GNUC__) && (__GNUC__ >= 7))
+#  define FALLTHROUGH __attribute__((fallthrough))
+#else
+#  define FALLTHROUGH
+#endif
+
 #define REQUIRES(msg, ...) class=typename std::enable_if<__VA_ARGS__::value>::type
 
 #include <string>