diff --git a/CMakeLists.txt b/CMakeLists.txt
index a2c03fd..9eada68 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -116,17 +116,20 @@
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LLVM_DEFAULT_TARGET_TRIPLE})
-  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE})
+  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE PATH
+      "Path where built libunwind libraries should be installed.")
   if(LIBCXX_LIBDIR_SUBDIR)
     string(APPEND LIBUNWIND_LIBRARY_DIR /${LIBUNWIND_LIBDIR_SUBDIR})
     string(APPEND LIBUNWIND_INSTALL_LIBRARY_DIR /${LIBUNWIND_LIBDIR_SUBDIR})
   endif()
 elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
-  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX})
+  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX} CACHE PATH
+      "Path where built libunwind libraries should be installed.")
 else()
   set(LIBUNWIND_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBUNWIND_LIBDIR_SUFFIX})
-  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX})
+  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX} CACHE PATH
+      "Path where built libunwind libraries should be installed.")
 endif()
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
diff --git a/docs/BuildingLibunwind.rst b/docs/BuildingLibunwind.rst
index ad9dee0..9b11042 100644
--- a/docs/BuildingLibunwind.rst
+++ b/docs/BuildingLibunwind.rst
@@ -159,3 +159,10 @@
 .. option:: LIBUNWIND_SYSROOT
 
   Sysroot for cross compiling
+
+.. option:: LIBUNWIND_INSTALL_LIBRARY_DIR:PATH
+
+  **Default**: ``lib${LIBUNWIND_LIBDIR_SUFFIX}``
+
+  Path where built libunwind libraries should be installed. If a relative path,
+  relative to ``CMAKE_INSTALL_PREFIX``.