diff --git a/Gemfile.lock b/Gemfile.lock
index 149ed9d..332e247 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,7 +7,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     diff-lcs (1.3)
-    rake (10.5.0)
+    rake (13.0.1)
     rspec (3.8.0)
       rspec-core (~> 3.8.0)
       rspec-expectations (~> 3.8.0)
@@ -28,7 +28,7 @@ PLATFORMS
 DEPENDENCIES
   bundler (~> 2.0)
   lambda_calculus!
-  rake (~> 10.0)
+  rake (~> 13.0)
   rspec (= 3.8.0)
 
 BUNDLED WITH
diff --git a/lambda_calculus.gemspec b/lambda_calculus.gemspec
index ed5706e..4962094 100644
--- a/lambda_calculus.gemspec
+++ b/lambda_calculus.gemspec
@@ -36,6 +36,6 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_development_dependency "bundler", "~> 2.0"
-  spec.add_development_dependency "rake", "~> 10.0"
+  spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rspec", "3.8.0"
 end