diff --git a/.travis.yml b/.travis.yml
index fdf5766e7..104fc45f9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,13 +2,9 @@ before_install:
   - gem update --system 2.7.9
   - gem install bundler:1.17.3
   - rvm @global do gem uninstall did_you_mean
-  - # Travis's rvm 2.5.5 installation comes with bundler 2.0.1 for some reason.
-  - if [ "$TRAVIS_RUBY_VERSION" = "2.5.5" ]; then rvm @global do gem uninstall bundler -v 2.0.1 -x; fi
 bundler_args: --without development
 language: ruby
 rvm:
-  - 1.8.7
-  - 1.9.3
   - 2.0.0
   - 2.1.10
   - 2.2.10
diff --git a/Gemfile b/Gemfile
index dd829a330..4d6779ffd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,42 +1,30 @@
 source "https://rubygems.org"
 
 gem "rake", "< 11"
-gem "rdoc", "~> 4.2.2" # This is to support Ruby 1.8 and 1.9
 
 group :development do
   gem "pry"
   platforms :ruby_21 do
     gem "pry-byebug"
   end
-  platforms :ruby_19, :ruby_20 do
+  platforms :ruby_20 do
     gem "pry-debugger"
     gem "pry-stack_explorer"
   end
 end
 
 group :test do
-  gem "addressable", "~> 2.3.6", :platforms => [:ruby_18]
   gem "childlabor"
   gem "coveralls", ">= 0.8.19"
-  gem "json", "< 2" # This is to support Ruby 1.8 and 1.9
-  gem "mime-types", "~> 1.25", :platforms => [:jruby, :ruby_18]
-  gem "rest-client", "~> 1.6.0", :platforms => [:jruby, :ruby_18]
+  gem "mime-types", "~> 1.25", :platforms => [:jruby]
+  gem "rest-client", "~> 1.6.0", :platforms => [:jruby]
   gem "rspec", ">= 3"
   gem "rspec-mocks", ">= 3"
-  gem "rubocop", ">= 0.19", :platforms => [:ruby_20, :ruby_21, :ruby_22, :ruby_23, :ruby_24]
+  gem "rubocop", ">= 0.19"
   gem "simplecov", ">= 0.13"
-  gem "term-ansicolor", "~> 1.3.2" # This is to support Ruby 1.8 and 1.9
-  gem "tins", "< 1.7" # This is to support Ruby 1.8 and 1.9
-  if RUBY_VERSION < "1.9.3"
-    gem "webmock", ">= 1.20", "< 2" # This is to support Ruby 1.8 and 1.9.2
-    gem "hashdiff", "< 0.3.6" # Hashdiff 0.3.6 no longer supports Ruby 1.8
-  else
-    gem "webmock"
-  end
-  if RUBY_VERSION >= '1.9'
-    # `did_you_mean` can't build with Ruby 1.8.
-    gem 'did_you_mean'
-  end
+  gem "webmock"
 end
 
+gem 'did_you_mean'
+
 gemspec
diff --git a/lib/thor/base.rb b/lib/thor/base.rb
index a07ee6140..a2b8ab34b 100644
--- a/lib/thor/base.rb
+++ b/lib/thor/base.rb
@@ -1,6 +1,5 @@
 require "thor/command"
 require "thor/core_ext/hash_with_indifferent_access"
-require "thor/core_ext/ordered_hash"
 require "thor/error"
 require "thor/invocation"
 require "thor/parser"
@@ -354,22 +353,22 @@ def group(name = nil)
       # Returns the commands for this Thor class.
       #
       # ==== Returns
-      # OrderedHash:: An ordered hash with commands names as keys and Thor::Command
-      #               objects as values.
+      # Hash:: An ordered hash with commands names as keys and Thor::Command
+      #        objects as values.
       #
       def commands
-        @commands ||= Thor::CoreExt::OrderedHash.new
+        @commands ||= Hash.new
       end
       alias_method :tasks, :commands
 
       # Returns the commands for this Thor class and all subclasses.
       #
       # ==== Returns
-      # OrderedHash:: An ordered hash with commands names as keys and Thor::Command
-      #               objects as values.
+      # Hash:: An ordered hash with commands names as keys and Thor::Command
+      #        objects as values.
       #
       def all_commands
-        @all_commands ||= from_superclass(:all_commands, Thor::CoreExt::OrderedHash.new)
+        @all_commands ||= from_superclass(:all_commands, Hash.new)
         @all_commands.merge!(commands)
       end
       alias_method :all_tasks, :all_commands
diff --git a/lib/thor/command.rb b/lib/thor/command.rb
index e3487ce5d..56ca79538 100644
--- a/lib/thor/command.rb
+++ b/lib/thor/command.rb
@@ -97,8 +97,7 @@ def sans_backtrace(backtrace, caller) #:nodoc:
     def handle_argument_error?(instance, error, caller)
       not_debugging?(instance) && (error.message =~ /wrong number of arguments/ || error.message =~ /given \d*, expected \d*/) && begin
         saned = sans_backtrace(error.backtrace, caller)
-        # Ruby 1.9 always include the called method in the backtrace
-        saned.empty? || (saned.size == 1 && RUBY_VERSION >= "1.9")
+        saned.empty? || saned.size == 1
       end
     end
 
diff --git a/lib/thor/core_ext/ordered_hash.rb b/lib/thor/core_ext/ordered_hash.rb
deleted file mode 100644
index 778772f3d..000000000
--- a/lib/thor/core_ext/ordered_hash.rb
+++ /dev/null
@@ -1,129 +0,0 @@
-class Thor
-  module CoreExt
-    class OrderedHash < ::Hash
-      if RUBY_VERSION < "1.9"
-        def initialize(*args, &block)
-          super
-          @keys = []
-        end
-
-        def initialize_copy(other)
-          super
-          # make a deep copy of keys
-          @keys = other.keys
-        end
-
-        def []=(key, value)
-          @keys << key unless key?(key)
-          super
-        end
-
-        def delete(key)
-          if key? key
-            index = @keys.index(key)
-            @keys.delete_at index
-          end
-          super
-        end
-
-        def delete_if
-          super
-          sync_keys!
-          self
-        end
-
-        alias_method :reject!, :delete_if
-
-        def reject(&block)
-          dup.reject!(&block)
-        end
-
-        def keys
-          @keys.dup
-        end
-
-        def values
-          @keys.map { |key| self[key] }
-        end
-
-        def to_hash
-          self
-        end
-
-        def to_a
-          @keys.map { |key| [key, self[key]] }
-        end
-
-        def each_key
-          return to_enum(:each_key) unless block_given?
-          @keys.each { |key| yield(key) }
-          self
-        end
-
-        def each_value
-          return to_enum(:each_value) unless block_given?
-          @keys.each { |key| yield(self[key]) }
-          self
-        end
-
-        def each
-          return to_enum(:each) unless block_given?
-          @keys.each { |key| yield([key, self[key]]) }
-          self
-        end
-
-        def each_pair
-          return to_enum(:each_pair) unless block_given?
-          @keys.each { |key| yield(key, self[key]) }
-          self
-        end
-
-        alias_method :select, :find_all
-
-        def clear
-          super
-          @keys.clear
-          self
-        end
-
-        def shift
-          k = @keys.first
-          v = delete(k)
-          [k, v]
-        end
-
-        def merge!(other_hash)
-          if block_given?
-            other_hash.each { |k, v| self[k] = key?(k) ? yield(k, self[k], v) : v }
-          else
-            other_hash.each { |k, v| self[k] = v }
-          end
-          self
-        end
-
-        alias_method :update, :merge!
-
-        def merge(other_hash, &block)
-          dup.merge!(other_hash, &block)
-        end
-
-        # When replacing with another hash, the initial order of our keys must come from the other hash -ordered or not.
-        def replace(other)
-          super
-          @keys = other.keys
-          self
-        end
-
-        def inspect
-          "#<#{self.class} #{super}>"
-        end
-
-        private
-
-        def sync_keys!
-          @keys.delete_if { |k| !key?(k) }
-        end
-      end
-    end
-  end
-end
diff --git a/lib/thor/line_editor/basic.rb b/lib/thor/line_editor/basic.rb
index 76cefcd4c..32c3d862f 100644
--- a/lib/thor/line_editor/basic.rb
+++ b/lib/thor/line_editor/basic.rb
@@ -24,7 +24,7 @@ def get_input
           $stdin.gets
         else
           # Lazy-load io/console since it is gem-ified as of 2.3
-          require "io/console" if RUBY_VERSION > "1.9.2"
+          require "io/console"
           $stdin.noecho(&:gets)
         end
       end
diff --git a/lib/thor/line_editor/readline.rb b/lib/thor/line_editor/readline.rb
index 32446e333..e4a2c44c3 100644
--- a/lib/thor/line_editor/readline.rb
+++ b/lib/thor/line_editor/readline.rb
@@ -13,10 +13,7 @@ def self.available?
       def readline
         if echo?
           ::Readline.completion_append_character = nil
-          # Ruby 1.8.7 does not allow Readline.completion_proc= to receive nil.
-          if complete = completion_proc
-            ::Readline.completion_proc = complete
-          end
+          ::Readline.completion_proc = completion_proc
           ::Readline.readline(prompt, add_to_history?)
         else
           super
diff --git a/spec/core_ext/ordered_hash_spec.rb b/spec/core_ext/ordered_hash_spec.rb
deleted file mode 100644
index 614fc89f2..000000000
--- a/spec/core_ext/ordered_hash_spec.rb
+++ /dev/null
@@ -1,198 +0,0 @@
-require "helper"
-require "thor/core_ext/ordered_hash"
-
-describe Thor::CoreExt::OrderedHash do
-  subject { Thor::CoreExt::OrderedHash.new }
-
-  def populate_subject
-    subject[:foo] = "Foo!"
-    subject[:bar] = "Bar!"
-    subject[:baz] = "Baz!"
-    subject[:bop] = "Bop!"
-    subject[:bat] = "Bat!"
-  end
-
-  describe "#initialize" do
-    it "is empty" do
-      expect(subject).to be_empty
-    end
-  end
-
-  describe "#replace" do
-    before { populate_subject }
-    it "replaces the keys" do
-      other_hash = Thor::CoreExt::OrderedHash.new
-      other_hash[1] = "one"
-      other_hash[2] = "two"
-      other_hash[3] = "three"
-
-      subject.replace(other_hash)
-      expect(subject.keys).to eq [1,2,3]
-    end
-  end
-
-  describe "#[]" do
-    it "returns nil for an undefined key" do
-      expect(subject[:boom]).to be nil
-    end
-
-    before { populate_subject }
-    it "returns the value for each key" do
-      expect(subject[:foo]).to eq "Foo!"
-    end
-  end
-
-  describe "#[]=" do
-    it "does not duplicate keys" do
-      subject[:key] = 1
-      subject[:key] = 2
-
-      expect(subject.keys.size).to eq 1
-      expect(subject[:key]).to eq 2
-    end
-
-   it "does not move an overwritten node to the end of the ordering" do
-     populate_subject
-
-     subject[:baz] = "Bip!"
-     expect(subject.values).to eq(["Foo!", "Bar!", "Bip!", "Bop!", "Bat!"])
-
-     subject[:foo] = "Bip!"
-     expect(subject.values).to eq(["Bip!", "Bar!", "Bip!", "Bop!", "Bat!"])
-
-     subject[:bat] = "Bip!"
-     expect(subject.values).to eq(["Bip!", "Bar!", "Bip!", "Bop!", "Bip!"])
-   end
-  end
-
-  describe "#clear" do
-    before { populate_subject }
-    it "clears the keys" do
-      subject.clear
-      expect(subject.keys).to be_empty
-    end
-  end
-
-  describe "#shift" do
-    before { populate_subject }
-    it "pops the first key/value" do
-      arr = subject.shift
-      expect(arr).to eq [:foo, "Foo!"]
-    end
-
-    it "removes the key" do
-      subject.shift
-      expect(subject.keys).to_not include(:foo)
-    end
-  end
-
-  describe "#each" do
-    before { populate_subject }
-    it "iterates through the keys and values in order of assignment" do
-      arr = []
-      subject.each do |key, value|
-        arr << [key, value]
-      end
-
-     expect(arr).to eq([[:foo, "Foo!"], [:bar, "Bar!"], [:baz, "Baz!"],
-                        [:bop, "Bop!"], [:bat, "Bat!"]])
-    end
-  end
-
-  describe "#merge!" do
-    it "modifies the existing object" do
-      populate_subject
-
-      other_hash = Thor::CoreExt::OrderedHash.new
-      other_hash[1] = "one"
-      other_hash[2] = "two"
-      other_hash[3] = "three"
-
-      subject.merge!(other_hash)
-
-      expect(subject.values).to eq(["Foo!", "Bar!", "Baz!", "Bop!", "Bat!", "one", "two", "three"])
-    end
-  end
-
-  describe "#merge" do
-    it "appends another ordered hash while preserving ordering" do
-      populate_subject
-
-      other_hash = Thor::CoreExt::OrderedHash.new
-      other_hash[1] = "one"
-      other_hash[2] = "two"
-      other_hash[3] = "three"
-
-
-      merged_list = subject.merge(other_hash)
-      expect(merged_list.values).to eq(["Foo!", "Bar!", "Baz!", "Bop!", "Bat!", "one", "two", "three"])
-    end
-
-    it "overwrites hash keys with matching appended keys" do
-      populate_subject
-
-      other_hash = Thor::CoreExt::OrderedHash.new
-      other_hash[:bar] = "bar"
-
-      expect(subject.merge(other_hash)[:bar]).to eq("bar")
-      expect(subject[:bar]).to eq("Bar!")
-    end
-  end
-
-  describe "#to_a" do
-    before { populate_subject }
-    it "converts to an array" do
-      expect(subject.to_a).to eq([[:foo, "Foo!"], [:bar, "Bar!"], [:baz, "Baz!"], [:bop, "Bop!"], [:bat, "Bat!"]])
-    end
-  end
-
-  describe "#keys" do
-    context "when list is unpopulated" do
-      it "has an empty keys list" do
-        expect(subject.keys).to be_empty
-      end
-    end
-
-    it "returns the keys in order of insertion" do
-      populate_subject
-      expect(subject.keys).to eq([:foo, :bar, :baz, :bop, :bat])
-    end
-  end
-
-  describe "#values" do
-    it "returns the values in order of insertion" do
-      populate_subject
-      expect(subject.values).to eq(["Foo!", "Bar!", "Baz!", "Bop!", "Bat!"])
-    end
-
-    context "when list is unpopulated" do
-      it "has an empty list" do
-        list = described_class.new
-        expect(list.values).to be_empty
-      end
-    end
-  end
-
-  describe "#delete" do
-    before { populate_subject }
-    it "deletes the value given the key" do
-      expect(subject.delete(:baz)).to eq("Baz!")
-      expect(subject.values).to eq(["Foo!", "Bar!", "Bop!", "Bat!"])
-
-      expect(subject.delete(:foo)).to eq("Foo!")
-      expect(subject.values).to eq(["Bar!", "Bop!", "Bat!"])
-
-      expect(subject.delete(:bat)).to eq("Bat!")
-      expect(subject.values).to eq(["Bar!", "Bop!"])
-    end
-
-    it "returns nil if the value to be deleted can't be found" do
-      expect(subject.delete(:nothing)).to be nil
-    end
-
-    it "deletes the given key" do
-      subject.delete(:baz)
-      expect(subject.keys).to_not include(:baz)
-    end
-  end
-end
diff --git a/spec/helper.rb b/spec/helper.rb
index 993448d40..d51d6516c 100644
--- a/spec/helper.rb
+++ b/spec/helper.rb
@@ -1,15 +1,13 @@
 $TESTING = true
 
-if RUBY_VERSION >= "1.9"
-  require "simplecov"
-  require "coveralls"
+require "simplecov"
+require "coveralls"
 
-  SimpleCov.formatters = [SimpleCov::Formatter::HTMLFormatter, Coveralls::SimpleCov::Formatter]
+SimpleCov.formatters = [SimpleCov::Formatter::HTMLFormatter, Coveralls::SimpleCov::Formatter]
 
-  SimpleCov.start do
-    add_filter "/spec"
-    minimum_coverage(90)
-  end
+SimpleCov.start do
+  add_filter "/spec"
+  minimum_coverage(90)
 end
 
 $LOAD_PATH.unshift(File.join(File.dirname(__FILE__), "..", "lib"))
@@ -28,7 +26,6 @@
 $0 = "thor"
 $thor_runner = true
 ARGV.clear
-Encoding.default_external = Encoding::UTF_8 if RUBY_VERSION > '1.8.7' && RUBY_VERSION < '2.0.0'
 Thor::Base.shell = Thor::Shell::Basic
 
 # Load fixtures
diff --git a/spec/invocation_spec.rb b/spec/invocation_spec.rb
index 3241a1e0d..eb6d805d2 100644
--- a/spec/invocation_spec.rb
+++ b/spec/invocation_spec.rb
@@ -61,13 +61,7 @@
     it "returns the command chain" do
       expect(I.new.invoke("two")).to eq([:two])
 
-      if RUBY_VERSION < "1.9.3"
-        result = J.start(%w(one two))
-        expect(result).to include(:one)
-        expect(result).to include(:two)
-      else
-        expect(J.start(%w(one two))).to eq([:one, :two])
-      end
+      expect(J.start(%w(one two))).to eq([:one, :two])
     end
 
     it "dump configuration values to be used in the invoked class" do
diff --git a/spec/line_editor/readline_spec.rb b/spec/line_editor/readline_spec.rb
index b2b0712d6..df426d3b4 100644
--- a/spec/line_editor/readline_spec.rb
+++ b/spec/line_editor/readline_spec.rb
@@ -23,14 +23,14 @@
   describe "#readline" do
     it "invokes the readline library" do
       expect(::Readline).to receive(:readline).with("> ", true).and_return("foo")
-      expect(::Readline).not_to receive(:completion_proc=)
+      expect(::Readline).to receive(:completion_proc=)
       editor = Thor::LineEditor::Readline.new("> ", {})
       expect(editor.readline).to eq("foo")
     end
 
     it "supports the add_to_history option" do
       expect(::Readline).to receive(:readline).with("> ", false).and_return("foo")
-      expect(::Readline).not_to receive(:completion_proc=)
+      expect(::Readline).to receive(:completion_proc=)
       editor = Thor::LineEditor::Readline.new("> ", :add_to_history => false)
       expect(editor.readline).to eq("foo")
     end
diff --git a/spec/script_exit_status_spec.rb b/spec/script_exit_status_spec.rb
index 9d987185c..49ed5439c 100644
--- a/spec/script_exit_status_spec.rb
+++ b/spec/script_exit_status_spec.rb
@@ -26,4 +26,4 @@ def thor_command(command)
   it "a command that does not raise a Thor::Error exits with a status of 0" do
     expect(thor_command("ok")).to eq(0)
   end
-end if RUBY_VERSION > "1.8.7"
+end
diff --git a/spec/util_spec.rb b/spec/util_spec.rb
index af6812053..2182bed89 100644
--- a/spec/util_spec.rb
+++ b/spec/util_spec.rb
@@ -17,7 +17,7 @@ def self.clear_user_home!
     end
 
     it "returns nil if the namespace can't be found" do
-      expect(Thor::Util.find_by_namespace("thor:core_ext:ordered_hash")).to be nil
+      expect(Thor::Util.find_by_namespace("thor:core_ext:hash_with_indifferent_access")).to be nil
     end
 
     it "returns a class if it matches the namespace" do
@@ -39,7 +39,7 @@ def self.clear_user_home!
     end
 
     it "accepts class and module objects" do
-      expect(Thor::Util.namespace_from_thor_class(Thor::CoreExt::OrderedHash)).to eq("thor:core_ext:ordered_hash")
+      expect(Thor::Util.namespace_from_thor_class(Thor::CoreExt::HashWithIndifferentAccess)).to eq("thor:core_ext:hash_with_indifferent_access")
       expect(Thor::Util.namespace_from_thor_class(Thor::Util)).to eq("thor:util")
     end
 
diff --git a/thor.gemspec b/thor.gemspec
index b882721c8..a81f5f5bb 100644
--- a/thor.gemspec
+++ b/thor.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
   spec.licenses = %w(MIT)
   spec.name = "thor"
   spec.require_paths = %w(lib)
-  spec.required_ruby_version = ">= 1.8.7"
+  spec.required_ruby_version = ">= 2.0.0"
   spec.required_rubygems_version = ">= 1.3.5"
   spec.summary = spec.description
   spec.version = Thor::VERSION