diff --git a/ChangeLog.d/stop_cmake_out_of_build_running_on_16.04.txt b/ChangeLog.d/stop_cmake_out_of_build_running_on_16.04.txt
new file mode 100644
index 000000000..000b4e7b4
--- /dev/null
+++ b/ChangeLog.d/stop_cmake_out_of_build_running_on_16.04.txt
@@ -0,0 +1,4 @@
+Bugfix
+   * Prevent CMake out of source tests from running on Ubuntu 16.04, as this can
+     cause failures due to race conditions with generated files.
+
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 2d6538552..c07ef34f5 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2940,6 +2940,36 @@ component_test_valgrind () {
     fi
 }
 
+support_test_cmake_out_of_source () {
+    distrib_id=""
+    distrib_ver=""
+    distrib_ver_minor=""
+    distrib_ver_major=""
+
+    # Attempt to parse lsb-release to find out distribution and version. If not
+    # found this should fail safe (test is supported).
+    if [[ -f /etc/lsb-release ]]; then
+
+        while read -r lsb_line; do
+            case "$lsb_line" in
+                "DISTRIB_ID"*) distrib_id=${lsb_line/#DISTRIB_ID=};;
+                "DISTRIB_RELEASE"*) distrib_ver=${lsb_line/#DISTRIB_RELEASE=};;
+            esac
+        done < /etc/lsb-release
+
+        distrib_ver_major="${distrib_ver%%.*}"
+        distrib_ver="${distrib_ver#*.}"
+        distrib_ver_minor="${distrib_ver%%.*}"
+    fi
+
+    # Running the out of source CMake test on Ubuntu 16.04 using more than one
+    # processor (as the CI does) can create a race condition whereby the build
+    # fails to see a generated file, despite that file actually having been
+    # generated. This problem appears to go away with 18.04 or newer, so make
+    # the out of source tests unsupported on Ubuntu 16.04.
+    [ "$distrib_id" != "Ubuntu" ] || [ "$distrib_ver_major" -gt 16 ]
+}
+
 component_test_cmake_out_of_source () {
     msg "build: cmake 'out-of-source' build"
     MBEDTLS_ROOT_DIR="$PWD"