diff --git a/build/tools/travis-ci.sh b/build/tools/travis-ci.sh
index b804e53bef..37eb8b94f6 100755
--- a/build/tools/travis-ci.sh
+++ b/build/tools/travis-ci.sh
@@ -84,25 +84,28 @@ case $wxTOOLSET in
 
             error_opts="-Werror $allow_warn_opt"
             wxMAKEFILE_CXXFLAGS="$wxMAKEFILE_CXXFLAGS $error_opts"
-            wxMAKEFILE_ERROR_CXXFLAGS="CXXFLAGS=$error_opts"
+            wxMAKEFILE_ERROR_CXXFLAGS=("CXXFLAGS=$error_opts")
+        else
+            wxMAKEFILE_ERROR_CXXFLAGS=()
         fi
 
+        wxMAKEFILE_FLAGS=()
         if [ -n "$wxMAKEFILE_CXXFLAGS" ]; then
-            wxMAKEFILE_FLAGS="CXXFLAGS=$wxMAKEFILE_CXXFLAGS"
+            wxMAKEFILE_FLAGS+=("CXXFLAGS=$wxMAKEFILE_CXXFLAGS")
         fi
         if [ -n "$wxMAKEFILE_LDFLAGS" ]; then
-            wxMAKEFILE_FLAGS="$wxMAKEFILE_FLAGS LDFLAGS=$wxMAKEFILE_LDFLAGS"
+            wxMAKEFILE_FLAGS+=("LDFLAGS=$wxMAKEFILE_LDFLAGS")
         fi
 
         echo 'travis_fold:start:building'
         echo 'Building...'
-        make -k $wxBUILD_ARGS $wxMAKEFILE_ERROR_CXXFLAGS
+        make -k $wxBUILD_ARGS "${wxMAKEFILE_ERROR_CXXFLAGS[@]}"
         echo 'travis_fold:end:building'
 
         echo 'travis_fold:start:tests'
         echo 'Building tests...'
         [ "$wxSKIP_GUI" = 1 ] || make -C tests $wxBUILD_ARGS failtest
-        make -k -C tests $wxBUILD_ARGS $wxMAKEFILE_FLAGS
+        make -k -C tests $wxBUILD_ARGS "${wxMAKEFILE_FLAGS[@]}"
         echo 'travis_fold:end:tests'
 
         if [ "$wxSKIP_TESTING" = 1 ]; then
@@ -129,7 +132,7 @@ case $wxTOOLSET in
 
         echo 'travis_fold:start:samples'
         echo 'Building samples...'
-        (test "$wxSKIP_SAMPLES" && echo 'SKIPPED') || make -k $wxMAKEFILE_FLAGS samples
+        (test "$wxSKIP_SAMPLES" && echo 'SKIPPED') || make -k "${wxMAKEFILE_FLAGS[@]}" samples
         echo 'travis_fold:end:samples'
 
         echo 'travis_fold:start:install'
@@ -140,7 +143,7 @@ case $wxTOOLSET in
         echo 'travis_fold:start:testinstall'
         echo 'Testing installation...'
         make -C samples/minimal -f makefile.unx clean
-        make -C samples/minimal -f makefile.unx $wxMAKEFILE_FLAGS
+        make -C samples/minimal -f makefile.unx "${wxMAKEFILE_FLAGS[@]}"
         echo 'travis_fold:end:testinstall'
         ;;
 esac