diff --git a/.travis.yml b/.travis.yml
index 7c7570a..71561ea 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -148,6 +148,17 @@
             - clang-8
       env:
         - MATRIX_EVAL="CC=clang-8 CXX=clang++-8"
+    - os: linux
+      addons:
+        apt:
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-9 main'
+              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
+          packages:
+            - clang-9
+      env:
+        - MATRIX_EVAL="CC=clang-9 CXX=clang++-9"
 
 before_install:
   - eval "${MATRIX_EVAL}"