diff --git a/.github/workflows/iwyu.yml b/.github/workflows/iwyu.yml
new file mode 100644
index 0000000000..c4e3c82128
--- /dev/null
+++ b/.github/workflows/iwyu.yml
@@ -0,0 +1,108 @@
+name: Include What You Use
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  iwyu-check:
+    name: IWYU Header Dependencies Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install LLVM and IWYU from apt.llvm.org
+        run: |
+          # Add LLVM repository
+          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+          echo "deb http://apt.llvm.org/$(lsb_release -cs)/ llvm-toolchain-$(lsb_release -cs)-18 main" | sudo tee /etc/apt/sources.list.d/llvm.list
+
+          # Update and install packages
+          sudo apt-get update
+          sudo apt-get install -y \
+            llvm-18 \
+            llvm-18-dev \
+            clang-18 \
+            libclang-18-dev
+
+          # Install IWYU from Ubuntu repos (compatible with clang-18)
+          sudo apt-get install -y iwyu
+
+          # Create symlink if needed
+          if [ ! -f /usr/bin/include-what-you-use ] && [ -f /usr/bin/iwyu ]; then
+            sudo ln -s /usr/bin/iwyu /usr/bin/include-what-you-use
+          fi
+
+          # Verify IWYU installation
+          include-what-you-use --version || iwyu --version || echo "Warning: IWYU version check failed"
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get install -y \
+            libbz2-dev \
+            libxml2-dev \
+            libzip-dev \
+            liblua5.2-dev \
+            ccache
+
+          # Install TBB
+          TBB_VERSION=2021.12.0
+          TBB_URL="https://github.com/oneapi-src/oneTBB/releases/download/v${TBB_VERSION}/oneapi-tbb-${TBB_VERSION}-lin.tgz"
+          wget --tries 5 ${TBB_URL} -O onetbb.tgz
+          tar zxvf onetbb.tgz
+          sudo cp -a oneapi-tbb-${TBB_VERSION}/lib/. /usr/local/lib/
+          sudo cp -a oneapi-tbb-${TBB_VERSION}/include/. /usr/local/include/
+
+      - name: Install boost
+        uses: MarkusJx/install-boost@v2
+        id: install-boost
+        with:
+          boost_version: 1.85.0
+
+      - name: Configure CMake with IWYU
+        run: |
+          mkdir build
+          cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=Debug \
+            -DCMAKE_CXX_COMPILER=clang++-18 \
+            -DCMAKE_C_COMPILER=clang-18 \
+            -DENABLE_IWYU=ON \
+            -DENABLE_LTO=OFF
+        env:
+          Boost_ROOT: ${{ steps.install-boost.outputs.BOOST_ROOT }}
+
+      - name: Run IWYU
+        run: |
+          cd build
+          # Build to trigger IWYU checks (only building libraries, not all targets)
+          make -j$(nproc) osrm 2>&1 | tee iwyu.log || true
+
+          # Check if there are any IWYU warnings
+          if grep -q "should add these lines:" iwyu.log || grep -q "should remove these lines:" iwyu.log; then
+            echo "::warning::IWYU found issues with header dependencies"
+            echo "To fix header dependencies locally:"
+            echo "  1. Configure cmake with -DENABLE_IWYU=ON"
+            echo "  2. Build the project: make -j\$(nproc)"
+            echo "  3. Review IWYU suggestions and apply fixes"
+            echo "  4. You can use iwyu_tool.py and fix_includes.py for automated fixes"
+            # Don't fail the build for now, just warn
+            exit 0
+          else
+            echo "No IWYU issues found or IWYU not properly configured"
+          fi
+
+      - name: Upload IWYU log
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: iwyu-log
+          path: build/iwyu.log
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a6aac9106a..5a5b12bb06 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,6 +30,7 @@ option(ENABLE_CONAN "Use conan for dependencies" OFF)
 option(ENABLE_COVERAGE "Build with coverage instrumentalisation" OFF)
 option(ENABLE_DEBUG_LOGGING "Use debug logging in release mode" OFF)
 option(ENABLE_FUZZING "Fuzz testing using LLVM's libFuzzer" OFF)
+option(ENABLE_IWYU "Enable include-what-you-use checks" OFF)
 option(ENABLE_LTO "Use Link Time Optimisation" ON)
 option(ENABLE_NODE_BINDINGS "Build NodeJs bindings" OFF)
 option(ENABLE_SANITIZER "Use memory sanitizer for Debug build" OFF)
@@ -67,6 +68,22 @@ if (ENABLE_CLANG_TIDY)
   endif()
 endif()
 
+if (ENABLE_IWYU)
+  find_program(IWYU_COMMAND NAMES include-what-you-use iwyu)
+  if(NOT IWYU_COMMAND)
+    message(FATAL_ERROR "ENABLE_IWYU is ON but include-what-you-use is not found!")
+  else()
+    message(STATUS "Found include-what-you-use at ${IWYU_COMMAND}")
+    # Check if mapping file exists
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/iwyu.imp")
+      set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${IWYU_COMMAND};-Xiwyu;--mapping_file=${CMAKE_CURRENT_SOURCE_DIR}/iwyu.imp")
+      message(STATUS "Using IWYU mapping file: ${CMAKE_CURRENT_SOURCE_DIR}/iwyu.imp")
+    else()
+      set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${IWYU_COMMAND}")
+    endif()
+  endif()
+endif()
+
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 
 project(OSRM C CXX)
diff --git a/iwyu.imp b/iwyu.imp
new file mode 100644
index 0000000000..13bcfdf3b7
--- /dev/null
+++ b/iwyu.imp
@@ -0,0 +1,18 @@
+[
+  # Standard library mappings
+  { "include": ["<bits/fcntl-linux.h>", "private", "<fcntl.h>", "public"] },
+  { "include": ["<bits/shared_ptr.h>", "private", "<memory>", "public"] },
+  { "include": ["<bits/unique_ptr.h>", "private", "<memory>", "public"] },
+  { "include": ["<bits/std_function.h>", "private", "<functional>", "public"] },
+  { "include": ["<sys/types.h>", "public", "<cstdint>", "public"] },
+
+  # Third-party library mappings
+  { "include": ["<expat_external.h>", "public", "<expat.h>", "public"] },
+  { "include": ["<zconf.h>", "public", "<zlib.h>", "public"] },
+
+  # Boost mappings
+  { "include": ["@<boost/.*>", "public", "<boost/boost.hpp>", "public"] },
+
+  # TBB mappings
+  { "include": ["@<tbb/.*>", "public", "<tbb/tbb.h>", "public"] }
+]