diff --git a/.github/workflows/iwyu.yml b/.github/workflows/iwyu.yml
new file mode 100644
index 000000000..f52ac353e
--- /dev/null
+++ b/.github/workflows/iwyu.yml
@@ -0,0 +1,63 @@
+# Syntax reference https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
+# Environment reference https://help.github.com/en/actions/reference/virtual-environments-for-github-hosted-runners
+name: include-what-you-use
+
+on: workflow_dispatch
+
+jobs:
+  build:
+
+    runs-on: ubuntu-20.04
+
+    container:
+      image: "kalilinux/kali-rolling"
+
+    steps:
+      - uses: actions/checkout@v2
+
+      # TODO: the necessary packages are excessive - mostly because of Qt - use a pre-built image
+      - name: Install missing software
+        run: |
+          apt-get update
+          apt-get install -y cmake g++ make libz3-dev libpcre3-dev
+          apt-get install -y qtbase5-dev qttools5-dev libqt5charts5-dev
+          apt-get install -y wget iwyu
+
+      - name: Prepare CMake
+        run: |
+          mkdir cmake.output
+          cd cmake.output
+          cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DUSE_Z3=On -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=On -DBUILD_TESTS=On -DBUILD_GUI=On -DWITH_QCHART=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=On -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCPPCHK_GLIBCXX_DEBUG=Off -DUSE_MATCHCOMPILER=Off ..
+          cd ..
+
+      - name: Prepare CMake dependencies
+        run: |
+          # make sure the precompiled headers exist
+          #make -C cmake.output lib/CMakeFiles/lib_objs.dir/cmake_pch.hxx.cxx
+          #make -C cmake.output test/CMakeFiles/testrunner.dir/cmake_pch.hxx.cxx
+          # make sure the auto-generated GUI sources exist
+          make -C cmake.output autogen
+          # make sure the auto-generated GUI dependencies exist
+          make -C cmake.output gui-build-deps
+
+      - name: Build Qt mappings
+        run: |
+          wget https://raw.githubusercontent.com/include-what-you-use/include-what-you-use/master/mapgen/iwyu-mapgen-qt.py
+          python3 iwyu-mapgen-qt.py /usr/include/x86_64-linux-gnu/qt5/ > qt5.imp
+
+      # TODO: the mapping file causes a massive slowdown so we cannot use it at the moment.
+      #       add "-Xiwyu --mapping_file=qt5.imp" at the end of the whole command if we can use them.
+      - name: iwyu_tool
+        run: |
+          # do not fail for now so the output is being saved
+          iwyu_tool -p cmake.output -j $(nproc) -- -w > iwyu.log || true
+
+      - uses: actions/upload-artifact@v2
+        with:
+          name: Qt Mappings
+          path: ./qt5.imp
+
+      - uses: actions/upload-artifact@v2
+        with:
+          name: Logs
+          path: ./*.log
diff --git a/cli/cppcheckexecutor.cpp b/cli/cppcheckexecutor.cpp
index 6e79362d0..4d59d81f0 100644
--- a/cli/cppcheckexecutor.cpp
+++ b/cli/cppcheckexecutor.cpp
@@ -62,8 +62,7 @@
 #   include <ucontext.h>
 #endif
 #ifdef __linux__
-#include <sys/syscall.h>
-#include <sys/types.h>
+#include <syscall.h>
 #endif
 #endif
 
diff --git a/cli/main.cpp b/cli/main.cpp
index f8a89420b..82597a30b 100644
--- a/cli/main.cpp
+++ b/cli/main.cpp
@@ -59,15 +59,15 @@
  */
 
 
-#include "errortypes.h"
 #include "cppcheckexecutor.h"
 
+#ifdef NDEBUG
+#include "errortypes.h"
+
 #include <cstdlib>
 #include <exception>
-#include <string>
-
-#ifdef NDEBUG
 #include <iostream>
+#include <string>
 #endif
 
 #ifdef _WIN32
diff --git a/cli/threadexecutor.cpp b/cli/threadexecutor.cpp
index 90fd43aac..e22344c1d 100644
--- a/cli/threadexecutor.cpp
+++ b/cli/threadexecutor.cpp
@@ -38,6 +38,7 @@
 #ifdef __SVR4  // Solaris
 #include <sys/loadavg.h>
 #endif
+
 #ifdef THREADING_MODEL_FORK
 #if defined(__linux__)
 #include <sys/prctl.h>
@@ -45,8 +46,10 @@
 #include <sys/select.h>
 #include <sys/wait.h>
 #include <fcntl.h>
+#include <csignal>
 #include <unistd.h>
 #endif
+
 #ifdef THREADING_MODEL_WIN
 #include <future>
 #include <numeric>
diff --git a/externals/simplecpp/simplecpp.cpp b/externals/simplecpp/simplecpp.cpp
index 852a5b892..68ff803da 100644
--- a/externals/simplecpp/simplecpp.cpp
+++ b/externals/simplecpp/simplecpp.cpp
@@ -27,12 +27,13 @@
 #include <cstdlib>
 #include <cstring>
 #include <exception>
-#include <fstream>
+#include <fstream> // IWYU pragma: keep
 #include <iostream>
 #include <limits>
-#include <sstream>
+#include <sstream> // IWYU pragma: keep
 #include <stack>
 #include <stdexcept>
+#include <type_traits>
 #include <utility>
 
 #ifdef SIMPLECPP_WINDOWS
diff --git a/lib/analyzerinfo.cpp b/lib/analyzerinfo.cpp
index dd068ba55..e0f043f18 100644
--- a/lib/analyzerinfo.cpp
+++ b/lib/analyzerinfo.cpp
@@ -25,7 +25,7 @@
 #include <tinyxml2.h>
 #include <cstring>
 #include <map>
-#include <sstream>
+#include <sstream> // IWYU pragma: keep
 
 AnalyzerInformation::~AnalyzerInformation()
 {
diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index b3da83ec7..e1b966203 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -40,7 +40,6 @@
 #include <memory>
 #include <ostream>
 #include <set>
-#include <type_traits>
 #include <utility>
 #include <numeric>
 
diff --git a/lib/color.cpp b/lib/color.cpp
index 378daa143..9a62f415a 100644
--- a/lib/color.cpp
+++ b/lib/color.cpp
@@ -22,7 +22,7 @@
 #include <unistd.h>
 #endif
 #include <cstddef>
-#include <sstream>
+#include <sstream> // IWYU pragma: keep
 
 #ifdef _WIN32
 std::ostream& operator<<(std::ostream& os, const Color& /*c*/)
diff --git a/lib/errorlogger.cpp b/lib/errorlogger.cpp
index c7aef5a52..2cf52fab2 100644
--- a/lib/errorlogger.cpp
+++ b/lib/errorlogger.cpp
@@ -24,6 +24,7 @@
 #include "path.h"
 #include "token.h"
 #include "tokenlist.h"
+#include "utils.h"
 
 #include <algorithm>
 #include <array>
diff --git a/lib/importproject.cpp b/lib/importproject.cpp
index c5ea4e600..a2577b95b 100644
--- a/lib/importproject.cpp
+++ b/lib/importproject.cpp
@@ -29,7 +29,7 @@
 #include <algorithm>
 #include <cstdlib>
 #include <cstring>
-#include <fstream>
+#include <fstream> // IWYU pragma: keep
 #include <iostream>
 #include <iterator>
 
diff --git a/lib/pathanalysis.cpp b/lib/pathanalysis.cpp
index 1b9e7a300..a102da1de 100644
--- a/lib/pathanalysis.cpp
+++ b/lib/pathanalysis.cpp
@@ -27,6 +27,7 @@
 #include <memory>
 #include <string>
 #include <tuple>
+#include <type_traits>
 
 const Scope* PathAnalysis::findOuterScope(const Scope * scope)
 {
diff --git a/lib/programmemory.cpp b/lib/programmemory.cpp
index 96326f57d..7e8c937c9 100644
--- a/lib/programmemory.cpp
+++ b/lib/programmemory.cpp
@@ -35,7 +35,6 @@
 #include <list>
 #include <memory>
 #include <string>
-#include <type_traits>
 #include <utility>
 #include <vector>
 
diff --git a/lib/templatesimplifier.cpp b/lib/templatesimplifier.cpp
index 0b08eaff1..0adf7a145 100644
--- a/lib/templatesimplifier.cpp
+++ b/lib/templatesimplifier.cpp
@@ -33,7 +33,6 @@
 #include <map>
 #include <memory>
 #include <stack>
-#include <type_traits>
 #include <utility>
 
 static Token *skipRequires(Token *tok)
diff --git a/test/testrunner.cpp b/test/testrunner.cpp
index 7e85bd3ff..a76e3b60b 100644
--- a/test/testrunner.cpp
+++ b/test/testrunner.cpp
@@ -16,17 +16,18 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "errortypes.h"
 #include "options.h"
 #include "preprocessor.h"
 #include "testsuite.h"
 
 #include <cstdlib>
-#include <exception>
-#include <string>
 
 #ifdef NDEBUG
+#include "errortypes.h"    // for InternalError
+
+#include <exception>
 #include <iostream>
+#include <string>
 #endif
 
 int main(int argc, char *argv[])