diff --git a/CMakeLists.txt b/CMakeLists.txt
index c5fd56233..3dd2270f6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,6 +14,7 @@ option(ENABLE_ZLIB_SUPPORT "Build mbed TLS with zlib library." OFF)
 option(ENABLE_PROGRAMS "Build mbed TLS programs." ON)
 
 option(UNSAFE_BUILD "Allow unsafe builds. These builds ARE NOT SECURE." OFF)
+option(MBEDTLS_FATAL_WARNINGS "Compiler warnings treated as errors" ON)
 
 string(REGEX MATCH "Clang" CMAKE_COMPILER_IS_CLANG "${CMAKE_C_COMPILER_ID}")
 string(REGEX MATCH "GNU" CMAKE_COMPILER_IS_GNU "${CMAKE_C_COMPILER_ID}")
@@ -140,9 +141,9 @@ if(CMAKE_COMPILER_IS_GNU)
     set(CMAKE_C_FLAGS_RELEASE     "-O2")
     set(CMAKE_C_FLAGS_DEBUG       "-O0 -g3")
     set(CMAKE_C_FLAGS_COVERAGE    "-O0 -g3 --coverage")
-    set(CMAKE_C_FLAGS_ASAN        "-Werror -fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O3")
-    set(CMAKE_C_FLAGS_ASANDBG     "-Werror -fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
-    set(CMAKE_C_FLAGS_CHECK       "-Werror -Os")
+    set(CMAKE_C_FLAGS_ASAN        "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O3")
+    set(CMAKE_C_FLAGS_ASANDBG     "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
+    set(CMAKE_C_FLAGS_CHECK       "-Os")
     set(CMAKE_C_FLAGS_CHECKFULL   "${CMAKE_C_FLAGS_CHECK} -Wcast-qual")
 endif(CMAKE_COMPILER_IS_GNU)
 
@@ -151,23 +152,32 @@ if(CMAKE_COMPILER_IS_CLANG)
     set(CMAKE_C_FLAGS_RELEASE     "-O2")
     set(CMAKE_C_FLAGS_DEBUG       "-O0 -g3")
     set(CMAKE_C_FLAGS_COVERAGE    "-O0 -g3 --coverage")
-    set(CMAKE_C_FLAGS_ASAN        "-Werror -fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O3")
-    set(CMAKE_C_FLAGS_ASANDBG     "-Werror -fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
-    set(CMAKE_C_FLAGS_MEMSAN      "-Werror -fsanitize=memory -O3")
-    set(CMAKE_C_FLAGS_MEMSANDBG   "-Werror -fsanitize=memory -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls -fsanitize-memory-track-origins=2")
-    set(CMAKE_C_FLAGS_CHECK       "-Werror -Os")
+    set(CMAKE_C_FLAGS_ASAN        "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O3")
+    set(CMAKE_C_FLAGS_ASANDBG     "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
+    set(CMAKE_C_FLAGS_MEMSAN      "-fsanitize=memory -O3")
+    set(CMAKE_C_FLAGS_MEMSANDBG   "-fsanitize=memory -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls -fsanitize-memory-track-origins=2")
+    set(CMAKE_C_FLAGS_CHECK       "-Os")
 endif(CMAKE_COMPILER_IS_CLANG)
 
 if(CMAKE_COMPILER_IS_IAR)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} --warn_about_c_style_casts --warnings_are_errors -Ohz")
 endif(CMAKE_COMPILER_IS_IAR)
 
-if(CMAKE_COMPILER_IS_MSVC AND NOT UNSAFE_BUILD)
-    # Strictest warnings, and treat as errors
+if(CMAKE_COMPILER_IS_MSVC)
+    # Strictest warnings
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /W3")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /WX")
 endif(CMAKE_COMPILER_IS_MSVC)
 
+if(MBEDTLS_FATAL_WARNINGS)
+    if(CMAKE_COMPILER_IS_MSVC)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /WX")
+    endif(CMAKE_COMPILER_IS_MSVC)
+
+    if(CMAKE_COMPILER_IS_CLANG OR CMAKE_COMPILER_IS_GNU)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
+    endif(CMAKE_COMPILER_IS_CLANG OR CMAKE_COMPILER_IS_GNU)
+endif(MBEDTLS_FATAL_WARNINGS)
+
 if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
     if(CMAKE_COMPILER_IS_GNU OR CMAKE_COMPILER_IS_CLANG)
         set(CMAKE_SHARED_LINKER_FLAGS "--coverage")
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 14dfa221b..cd6cbde98 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -113,12 +113,6 @@ if(CMAKE_COMPILER_IS_CLANG)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wmissing-declarations -Wmissing-prototypes -Wdocumentation -Wno-documentation-deprecated-sync -Wunreachable-code")
 endif(CMAKE_COMPILER_IS_CLANG)
 
-if(UNSAFE_BUILD)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-error")
-    set(CMAKE_C_FLAGS_ASAN "${CMAKE_C_FLAGS_ASAN} -Wno-error")
-    set(CMAKE_C_FLAGS_ASANDBG "${CMAKE_C_FLAGS_ASANDBG} -Wno-error")
-endif(UNSAFE_BUILD)
-
 if(WIN32)
     set(libs ${libs} ws2_32)
 endif(WIN32)