diff --git a/.travis.yml b/.travis.yml
index 1599eb0e..2b0ac21a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -25,7 +25,7 @@ matrix:
       compiler: gcc
       install: ./ci/install-linux.sh && ./ci/log-config.sh
       script: ./ci/build-linux-autotools.sh
-      env: VERBOSE=1 CXX_FLAGS=-std=c++11
+      env: VERBOSE=1 CXXFLAGS=-std=c++11
     - os: linux
       group: deprecated-2017Q4
       compiler: gcc