diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0408aac7..5aa67331 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -212,14 +212,19 @@ if(UNITS_BUILD_FUZZ_TARGETS)
     add_subdirectory(FuzzTargets)
 elseif(UNITS_ENABLE_TESTS AND NOT CMAKE_VERSION VERSION_LESS 3.13)
     include(updateGitSubmodules)
-    enable_testing()
-    if(NOT EXISTS "${PROJECT_SOURCE_DIR}/ThirdParty/googletest/CMakeLists.txt")
-        submod_update(ThirdParty/googletest)
+    if(UNITS_ENABLE_SUBMODULE_UPDATE)
+        enable_testing()
+        if(NOT EXISTS "${PROJECT_SOURCE_DIR}/ThirdParty/googletest/CMakeLists.txt")
+            submod_update(ThirdParty/googletest)
+        endif()
+    else()
+        include(FindPkgConfig)
+        find_package(GTest REQUIRED)
+        pkg_check_modules(GMock gmock REQUIRED)
     endif()
     if(BUILD_TESTING)
         add_subdirectory(test)
     endif()
-
 elseif(UNITS_ENABLE_TESTS)
     message(WARNING "UNITS unit tests only supported under cmake 3.13 or greater")
 endif()
diff --git a/config/AddGoogletest.cmake b/config/AddGoogletest.cmake
index feb302db..681184aa 100644
--- a/config/AddGoogletest.cmake
+++ b/config/AddGoogletest.cmake
@@ -35,20 +35,26 @@ set(CMAKE_SUPPRESS_DEVELOPER_WARNINGS
     CACHE INTERNAL ""
 )
 
-add_subdirectory(
-    ${CMAKE_SOURCE_DIR}/ThirdParty/googletest ${CMAKE_BINARY_DIR}/ThirdParty/googletest
-    EXCLUDE_FROM_ALL
-)
-
-if(NOT MSVC)
-    target_compile_options(gtest PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions")
-    target_compile_options(gmock PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions")
-    target_compile_options(
-        gtest_main PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions"
-    )
-    target_compile_options(
-        gmock_main PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions"
+if(NOT GTest_FOUND)
+    add_subdirectory(
+        ${CMAKE_SOURCE_DIR}/ThirdParty/googletest
+        ${CMAKE_BINARY_DIR}/ThirdParty/googletest EXCLUDE_FROM_ALL
     )
+
+    if(NOT MSVC)
+        target_compile_options(
+            gtest PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions"
+        )
+        target_compile_options(
+            gmock PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions"
+        )
+        target_compile_options(
+            gtest_main PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions"
+        )
+        target_compile_options(
+            gmock_main PUBLIC "-Wno-undef" "-Wno-c++17-attribute-extensions"
+        )
+    endif()
 endif()
 
 if(GOOGLE_TEST_INDIVIDUAL)
@@ -90,7 +96,9 @@ hide_variable(BUILD_GTEST)
 hide_variable(INSTALL_GTEST)
 hide_variable(GTEST_HAS_ABSL)
 
-set_target_properties(gtest gtest_main gmock gmock_main PROPERTIES FOLDER "Extern")
+if(NOT GTest_FOUND)
+    set_target_properties(gtest gtest_main gmock gmock_main PROPERTIES FOLDER "Extern")
+endif()
 
 if(MSVC)
     # add_compile_options( /wd4459)