diff --git a/README.md b/README.md
index 126a9ec7..0f9aeba3 100644
--- a/README.md
+++ b/README.md
@@ -129,7 +129,7 @@ task default: 'bundle:audit'
 
 * [ruby] >= 1.9.3
 * [rubygems] >= 1.8
-* [thor] ~> 0.18
+* [thor] >= 0.18, < 2
 * [bundler] ~> 1.2
 
 ## Install
diff --git a/gemspec.yml b/gemspec.yml
index 96886849..ad53416f 100644
--- a/gemspec.yml
+++ b/gemspec.yml
@@ -10,5 +10,5 @@ required_ruby_version: ">= 1.9.3"
 required_rubygems_version: ">= 1.8.0"
 
 dependencies:
-  thor: ~> 0.18
+  thor: ">= 0.18, < 2"
   bundler: ">= 1.2.0, < 3"