diff --git a/lib/matrix.rb b/lib/matrix.rb
index 34602f5c40..b8139b547f 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -14,6 +14,8 @@
 
 require "e2mmap"
 
+require_relative "matrix/version"
+
 module ExceptionForMatrix # :nodoc:
   extend Exception2MessageMapper
   def_e2message(TypeError, "wrong argument type %s (expected %s)")
diff --git a/lib/matrix/matrix.gemspec b/lib/matrix/matrix.gemspec
index c94e8b7cf2..75f6b69a98 100644
--- a/lib/matrix/matrix.gemspec
+++ b/lib/matrix/matrix.gemspec
@@ -1,8 +1,15 @@
 # frozen_string_literal: true
 
+begin
+  require_relative "lib/matrix/version"
+rescue LoadError
+  # for Ruby core repository
+  require_relative "version"
+end
+
 Gem::Specification.new do |spec|
   spec.name          = "matrix"
-  spec.version       = "0.1.0"
+  spec.version       = Matrix::VERSION
   spec.authors       = ["Marc-Andre Lafortune"]
   spec.email         = ["ruby-core@marc-andre.ca"]
 
@@ -11,7 +18,7 @@ Gem::Specification.new do |spec|
   spec.homepage      = "https://github.com/ruby/matrix"
   spec.license       = "BSD-2-Clause"
 
-  spec.files         = [".gitignore", ".travis.yml", "Gemfile", "LICENSE.txt", "README.md", "Rakefile", "bin/console", "bin/setup", "lib/matrix.rb", "lib/matrix/eigenvalue_decomposition.rb", "lib/matrix/lup_decomposition.rb", "matrix.gemspec"]
+  spec.files         = [".gitignore", ".travis.yml", "Gemfile", "LICENSE.txt", "README.md", "Rakefile", "bin/console", "bin/setup", "lib/matrix.rb", "lib/matrix/eigenvalue_decomposition.rb", "lib/matrix/lup_decomposition.rb", "lib/matrix/version.rb", "matrix.gemspec"]
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
diff --git a/lib/matrix/version.rb b/lib/matrix/version.rb
new file mode 100644
index 0000000000..f88bf38d96
--- /dev/null
+++ b/lib/matrix/version.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class Matrix
+  VERSION = "0.1.0"
+end