diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@@ -227,7 +227,7 @@
 set_property(CACHE SANITIZER_TEST_CXX PROPERTY STRINGS ;${CXXLIBS})
 handle_default_cxx_lib(SANITIZER_TEST_CXX)
 
-option(COMPILER_RT_USE_LLVM_UNWINDER "Use the LLVM unwinder." OFF)
+option(COMPILER_RT_USE_LLVM_UNWINDER "Use the LLVM unwinder." ON)
 cmake_dependent_option(COMPILER_RT_ENABLE_STATIC_UNWINDER
   "Statically link the LLVM unwinder." OFF
   "COMPILER_RT_USE_LLVM_UNWINDER" OFF)
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -269,7 +269,7 @@
    libc++abi. Doing otherwise is an ODR violation." OFF)
 # Build libc++abi with libunwind. We need this option to determine whether to
 # link with libunwind or libgcc_s while running the test cases.
-option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)
+option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." ON)
 
 # Target options --------------------------------------------------------------
 option(LIBCXX_BUILD_32_BITS "Build 32 bit multilib libc++. This option is not supported anymore when building the runtimes. Please specify a full triple instead." ${LLVM_BUILD_32_BITS})
diff --git a/libcxx/cmake/caches/AArch64.cmake b/libcxx/cmake/caches/AArch64.cmake
--- a/libcxx/cmake/caches/AArch64.cmake
+++ b/libcxx/cmake/caches/AArch64.cmake
@@ -1,2 +1 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "aarch64-linux-gnu" CACHE STRING "")
diff --git a/libcxx/cmake/caches/AIX.cmake b/libcxx/cmake/caches/AIX.cmake
--- a/libcxx/cmake/caches/AIX.cmake
+++ b/libcxx/cmake/caches/AIX.cmake
@@ -13,6 +13,5 @@
 set(LIBCXXABI_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC OFF CACHE BOOL "")
 set(LIBCXX_CXX_ABI libcxxabi CACHE STRING "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBUNWIND_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBUNWIND_ENABLE_STATIC OFF CACHE BOOL "")
diff --git a/libcxx/cmake/caches/Apple.cmake b/libcxx/cmake/caches/Apple.cmake
--- a/libcxx/cmake/caches/Apple.cmake
+++ b/libcxx/cmake/caches/Apple.cmake
@@ -14,6 +14,7 @@
 
 set(LIBCXXABI_ENABLE_ASSERTIONS OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_FORGIVING_DYNAMIC_CAST ON CACHE BOOL "")
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # libunwind is built separately
 
 set(LIBCXX_TEST_CONFIG "apple-libc++-shared.cfg.in" CACHE STRING "")
 set(LIBCXXABI_TEST_CONFIG "apple-libc++abi-shared.cfg.in" CACHE STRING "")
diff --git a/libcxx/cmake/caches/Armv7Arm.cmake b/libcxx/cmake/caches/Armv7Arm.cmake
--- a/libcxx/cmake/caches/Armv7Arm.cmake
+++ b/libcxx/cmake/caches/Armv7Arm.cmake
@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv7l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-marm" CACHE STRING "")
 set(CMAKE_C_FLAGS "-marm" CACHE STRING "")
diff --git a/libcxx/cmake/caches/Armv7Thumb-no-exceptions.cmake b/libcxx/cmake/caches/Armv7Thumb-no-exceptions.cmake
--- a/libcxx/cmake/caches/Armv7Thumb-no-exceptions.cmake
+++ b/libcxx/cmake/caches/Armv7Thumb-no-exceptions.cmake
@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv7l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-mthumb" CACHE STRING "")
 set(CMAKE_C_FLAGS "-mthumb" CACHE STRING "")
diff --git a/libcxx/cmake/caches/Armv8Arm.cmake b/libcxx/cmake/caches/Armv8Arm.cmake
--- a/libcxx/cmake/caches/Armv8Arm.cmake
+++ b/libcxx/cmake/caches/Armv8Arm.cmake
@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv8l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-marm" CACHE STRING "")
 set(CMAKE_C_FLAGS "-marm" CACHE STRING "")
diff --git a/libcxx/cmake/caches/Armv8Thumb-no-exceptions.cmake b/libcxx/cmake/caches/Armv8Thumb-no-exceptions.cmake
--- a/libcxx/cmake/caches/Armv8Thumb-no-exceptions.cmake
+++ b/libcxx/cmake/caches/Armv8Thumb-no-exceptions.cmake
@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv8l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-mthumb" CACHE STRING "")
 set(CMAKE_C_FLAGS "-mthumb" CACHE STRING "")
diff --git a/libcxx/cmake/caches/Generic-merged.cmake b/libcxx/cmake/caches/Generic-merged.cmake
--- a/libcxx/cmake/caches/Generic-merged.cmake
+++ b/libcxx/cmake/caches/Generic-merged.cmake
@@ -5,7 +5,6 @@
 set(LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY ON CACHE BOOL "")
 
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY ON CACHE BOOL "")
 
diff --git a/libcxx/cmake/caches/Generic-msan.cmake b/libcxx/cmake/caches/Generic-msan.cmake
--- a/libcxx/cmake/caches/Generic-msan.cmake
+++ b/libcxx/cmake/caches/Generic-msan.cmake
@@ -1 +1,2 @@
 set(LLVM_USE_SANITIZER "MemoryWithOrigins" CACHE STRING "")
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # MSAN is compiled against the system unwinder, which leads to false positives
diff --git a/libcxx/cmake/caches/Generic-tsan.cmake b/libcxx/cmake/caches/Generic-tsan.cmake
--- a/libcxx/cmake/caches/Generic-tsan.cmake
+++ b/libcxx/cmake/caches/Generic-tsan.cmake
@@ -1 +1,2 @@
 set(LLVM_USE_SANITIZER "Thread" CACHE STRING "")
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # TSAN is compiled against the system unwinder, which leads to false positives
diff --git a/libcxx/cmake/caches/MinGW.cmake b/libcxx/cmake/caches/MinGW.cmake
--- a/libcxx/cmake/caches/MinGW.cmake
+++ b/libcxx/cmake/caches/MinGW.cmake
@@ -1,5 +1,4 @@
 set(LIBCXX_CXX_ABI libcxxabi CACHE STRING "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
diff --git a/libcxx/docs/BuildingLibcxx.rst b/libcxx/docs/BuildingLibcxx.rst
--- a/libcxx/docs/BuildingLibcxx.rst
+++ b/libcxx/docs/BuildingLibcxx.rst
@@ -346,7 +346,7 @@
 
 .. option:: LIBCXXABI_USE_LLVM_UNWINDER:BOOL
 
-  **Default**: ``OFF``
+  **Default**: ``ON``
 
   Build and use the LLVM unwinder. Note: This option can only be used when
   libc++abi is the C++ ABI library used.
diff --git a/libcxx/docs/ReleaseNotes/18.rst b/libcxx/docs/ReleaseNotes/18.rst
--- a/libcxx/docs/ReleaseNotes/18.rst
+++ b/libcxx/docs/ReleaseNotes/18.rst
@@ -134,3 +134,10 @@
 
 Build System Changes
 --------------------
+
+- ``LIBCXXABI_USE_LLVM_UNWINDER`` and ``COMPILER_RT_USE_LLVM_UNWINDER`` switched defaults from ``OFF`` to ``ON``.
+  This means that by default, libc++abi and compiler-rt will link against the LLVM provided ``libunwind`` library
+  instead of the system-provided unwinding library. If you are building the LLVM runtimes with the goal of shipping
+  them so that they can interoperate with other system-provided libraries that might be using a different unwinding
+  library (such as ``libgcc_s``), you should pass ``LIBCXXABI_USE_LLVM_UNWINDER=OFF`` and ``COMPILER_RT_USE_LLVM_UNWINDER=OFF``
+  to make sure the system-provided unwinding library is used by the LLVM runtimes.
diff --git a/libcxx/utils/ci/buildkite-pipeline.yml b/libcxx/utils/ci/buildkite-pipeline.yml
--- a/libcxx/utils/ci/buildkite-pipeline.yml
+++ b/libcxx/utils/ci/buildkite-pipeline.yml
@@ -538,24 +538,6 @@
           limit: 2
     timeout_in_minutes: 120
 
-  - label: "With LLVM's libunwind"
-    command: "libcxx/utils/ci/run-buildbot generic-with_llvm_unwinder"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
-        ENABLE_CLANG_TIDY: "On"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
   - label: "Modular build with Local Submodule Visibility"
     command: "libcxx/utils/ci/run-buildbot generic-modules-lsv"
     artifact_paths:
diff --git a/libcxx/utils/ci/run-buildbot b/libcxx/utils/ci/run-buildbot
--- a/libcxx/utils/ci/run-buildbot
+++ b/libcxx/utils/ci/run-buildbot
@@ -412,11 +412,6 @@
     check-runtimes
     check-abi-list
 ;;
-generic-with_llvm_unwinder)
-    clean
-    generate-cmake -DLIBCXXABI_USE_LLVM_UNWINDER=ON
-    check-runtimes
-;;
 #
 # Module builds
 #
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -46,7 +46,7 @@
 option(LIBCXXABI_ENABLE_ASSERTIONS "Enable assertions independent of build mode." ON)
 option(LIBCXXABI_ENABLE_PEDANTIC "Compile with pedantic enabled." OFF)
 option(LIBCXXABI_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF)
-option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)
+option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." ON)
 option(LIBCXXABI_ENABLE_STATIC_UNWINDER "Statically link the LLVM unwinder." OFF)
 option(LIBCXXABI_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF)
 option(LIBCXXABI_ENABLE_THREADS "Build with threads enabled" ON)