diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index 7e9171ab777dc..c4e63e15e2860 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -179,9 +179,20 @@ jobs:
 
 
   ubuntu-focal-native:
-    name: 'Ubuntu 20.04, CMake 3.16, downloaded Boost'
+    name: 'Ubuntu 20.04, CMake 3.16, Boost ${{ matrix.conf.boost_version }}'
     runs-on: ubuntu-20.04
 
+    strategy:
+      fail-fast: false
+      matrix:
+        conf:
+          - boost_version: '1.73.0'
+            boost_archive: 'boost_1_73_0'
+          - boost_version: '1.78.0'
+            boost_archive: 'boost_1_78_0'
+          - boost_version: '1.84.0'
+            boost_archive: 'boost_1_84_0'
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -203,8 +214,8 @@ jobs:
 
       - name: Download Boost
         run: |
-          curl --location --remote-name https://boostorg.jfrog.io/artifactory/main/release/1.84.0/source/boost_1_84_0.tar.gz
-          tar -xf boost_1_84_0.tar.gz
+          curl --location --remote-name https://boostorg.jfrog.io/artifactory/main/release/${{ matrix.conf.boost_version }}/source/${{ matrix.conf.boost_archive }}.tar.gz
+          tar -xf ${{ matrix.conf.boost_archive }}.tar.gz
 
       - name: Restore Ccache cache
         uses: actions/cache/restore@v4
@@ -216,7 +227,7 @@ jobs:
 
       - name: Generate build system
         run: |
-          cmake -B build -DCMAKE_C_COMPILER=gcc-10 -DCMAKE_CXX_COMPILER=g++-10 -DBoost_INCLUDE_DIR="${PWD}/boost_1_84_0" -DENABLE_WALLET=ON -DWITH_MINIUPNPC=ON -DWITH_NATPMP=ON -DWITH_ZMQ=ON -DWITH_USDT=ON -DWERROR=ON
+          cmake -B build -DCMAKE_C_COMPILER=gcc-10 -DCMAKE_CXX_COMPILER=g++-10 -DBoost_INCLUDE_DIR="${PWD}/${{ matrix.conf.boost_archive }}" -DENABLE_WALLET=ON -DWITH_EXTERNAL_SIGNER=ON -DWITH_MINIUPNPC=ON -DWITH_NATPMP=ON -DWITH_ZMQ=ON -DWITH_USDT=ON -DWERROR=ON
 
       - name: Build
         working-directory: build
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 589a6ecccfebd..2ad8b974cee30 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,6 +69,11 @@ tristate_option(WITH_USDT
   "if sys/sdt.h is found."
   AUTO
 )
+tristate_option(WITH_EXTERNAL_SIGNER
+  "Enable external signer support."
+  "if Boost.Process is found."
+  AUTO
+)
 
 option(BUILD_TESTS "Build test_bitcoin executable." ON)
 option(BUILD_BENCH "Build bench_bitcoin executable." ON)
@@ -413,6 +418,7 @@ message("  SQLite, descriptor wallets .......... ${WITH_SQLITE}")
 message("  Berkeley DB, legacy wallets ......... ${WITH_BDB}")
 message("Optional packages:")
 message("  GUI ................................. ${WITH_GUI}")
+message("  external signer ..................... ${WITH_EXTERNAL_SIGNER}")
 message("  NAT-PMP ............................. ${WITH_NATPMP}")
 message("  UPnP ................................ ${WITH_MINIUPNPC}")
 message("  ZeroMQ .............................. ${WITH_ZMQ}")
diff --git a/cmake/bitcoin-config.h.in b/cmake/bitcoin-config.h.in
index ebbb97562cdb0..2303359386704 100644
--- a/cmake/bitcoin-config.h.in
+++ b/cmake/bitcoin-config.h.in
@@ -215,4 +215,7 @@
 /* Define if Berkeley DB (BDB) support should be compiled in. */
 #cmakedefine USE_BDB
 
+/* Define if external signer support is enabled. */
+#cmakedefine ENABLE_EXTERNAL_SIGNER
+
 #endif //BITCOIN_CONFIG_H
diff --git a/cmake/module/AddBoostIfNeeded.cmake b/cmake/module/AddBoostIfNeeded.cmake
index 90f74d0ad2341..3890766b6c6f8 100644
--- a/cmake/module/AddBoostIfNeeded.cmake
+++ b/cmake/module/AddBoostIfNeeded.cmake
@@ -19,6 +19,7 @@ function(add_boost_if_needed)
 
   set(Boost_NO_BOOST_CMAKE ON)
   find_package(Boost 1.73.0 REQUIRED)
+  mark_as_advanced(Boost_INCLUDE_DIR)
   set_target_properties(Boost::headers PROPERTIES IMPORTED_GLOBAL TRUE)
   target_compile_definitions(Boost::headers INTERFACE
     # We don't use multi_index serialization.
@@ -54,5 +55,54 @@ function(add_boost_if_needed)
     endif()
   endif()
 
-  mark_as_advanced(Boost_INCLUDE_DIR)
+  if(WITH_EXTERNAL_SIGNER)
+    include(CheckCXXSourceCompiles)
+    set(CMAKE_REQUIRED_INCLUDES ${Boost_INCLUDE_DIR})
+    # Boost 1.78 requires the following workaround.
+    # See: https://github.com/boostorg/process/issues/235
+    set(CMAKE_REQUIRED_FLAGS "-Wno-error=narrowing")
+    # Boost 1.73 requires the following workaround on systems with
+    # libc<2.34 only, as newer libc has integrated the functionality
+    # of the libpthread library.
+    set(CMAKE_REQUIRED_LIBRARIES Threads::Threads)
+    check_cxx_source_compiles("
+      #define BOOST_PROCESS_USE_STD_FS
+      #include <boost/process.hpp>
+      #include <string>
+
+      int main()
+      {
+        namespace bp = boost::process;
+        bp::opstream stdin_stream;
+        bp::ipstream stdout_stream;
+        bp::child c(\"dummy\", bp::std_out > stdout_stream, bp::std_err > stdout_stream, bp::std_in < stdin_stream);
+        stdin_stream << std::string{\"test\"} << std::endl;
+        if (c.running()) c.terminate();
+        c.wait();
+        c.exit_code();
+      }
+      " HAVE_BOOST_PROCESS
+    )
+    if(HAVE_BOOST_PROCESS)
+      if(WIN32)
+        # Boost Process for Windows uses Boost ASIO. Boost ASIO performs
+        # pre-main init of Windows networking libraries, which we do not
+        # want.
+        set(WITH_EXTERNAL_SIGNER OFF PARENT_SCOPE)
+        set(ENABLE_EXTERNAL_SIGNER OFF PARENT_SCOPE)
+      else()
+        set(WITH_EXTERNAL_SIGNER ON PARENT_SCOPE)
+        set(ENABLE_EXTERNAL_SIGNER ON PARENT_SCOPE)
+        target_compile_definitions(Boost::headers INTERFACE
+          BOOST_PROCESS_USE_STD_FS
+        )
+      endif()
+    elseif(WITH_EXTERNAL_SIGNER STREQUAL "AUTO")
+      set(WITH_EXTERNAL_SIGNER OFF PARENT_SCOPE)
+      set(ENABLE_EXTERNAL_SIGNER OFF PARENT_SCOPE)
+    else()
+      message(FATAL_ERROR "External signing is not supported for this Boost version.")
+    endif()
+  endif()
+
 endfunction()