diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4c6b1f103..950a82395 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Xcodeproj Changelog
 
-## Master
+## 1.5.9 (2018-05-15)
 
 ##### Enhancements
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 212de6f94..ea274fb71 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -14,7 +14,7 @@ GIT
 PATH
   remote: .
   specs:
-    xcodeproj (1.5.8)
+    xcodeproj (1.5.9)
       CFPropertyList (>= 2.3.3, < 4.0)
       atomos (~> 0.1.2)
       claide (>= 1.0.2, < 2.0)
diff --git a/lib/xcodeproj/gem_version.rb b/lib/xcodeproj/gem_version.rb
index 1b7b7478f..25c68ab93 100644
--- a/lib/xcodeproj/gem_version.rb
+++ b/lib/xcodeproj/gem_version.rb
@@ -1,5 +1,5 @@
 module Xcodeproj
   # The version of the xcodeproj gem.
   #
-  VERSION = '1.5.8'.freeze unless defined? Xcodeproj::VERSION
+  VERSION = '1.5.9'.freeze unless defined? Xcodeproj::VERSION
 end