diff --git a/.travis.yml b/.travis.yml
index 5a4f48c..fb8310c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,6 +6,11 @@ php:
   - 5.4
   - hhvm
 
-install: composer install
+install: composer require --no-update guzzlehttp/guzzle $GUZZLE_VERSION; composer update
 
 script: vendor/bin/phpunit
+
+env:
+  - GUZZLE_VERSION: 4.2
+  - GUZZLE_VERSION: 5.0
+  - GUZZLE_VERSION: 5.2