diff --git a/lib/did_you_mean.rb b/lib/did_you_mean.rb
index 6d3a6e8bda..0aef324059 100644
--- a/lib/did_you_mean.rb
+++ b/lib/did_you_mean.rb
@@ -86,11 +86,24 @@ require_relative 'did_you_mean/tree_spell_checker'
 #
 module DidYouMean
   # Map of error types and spell checker objects.
-  SPELL_CHECKERS = Hash.new(NullChecker)
+  @spell_checkers = Hash.new(NullChecker)
+
+  # Returns a sharable hash map of error types and spell checker objects.
+  def self.spell_checkers
+    @spell_checkers
+  end
 
   # Adds +DidYouMean+ functionality to an error using a given spell checker
   def self.correct_error(error_class, spell_checker)
-    SPELL_CHECKERS[error_class.name] = spell_checker
+    if defined?(Ractor)
+      new_mapping = { **@spell_checkers, error_class.name => spell_checker }
+      new_mapping.default = NullChecker
+
+      @spell_checkers = Ractor.make_shareable(new_mapping)
+    else
+      spell_checkers[error_class.name] = spell_checker
+    end
+
     error_class.prepend(Correctable) unless error_class < Correctable
   end
 
@@ -100,15 +113,23 @@ module DidYouMean
   correct_error LoadError, RequirePathChecker if RUBY_VERSION >= '2.8.0'
   correct_error NoMatchingPatternKeyError, PatternKeyNameChecker if defined?(::NoMatchingPatternKeyError)
 
+  # TODO: Remove on 3.3:
+  SPELL_CHECKERS = @spell_checkers
+  deprecate_constant :SPELL_CHECKERS
+
   # Returns the currently set formatter. By default, it is set to +DidYouMean::Formatter+.
   def self.formatter
-    @formatter
+    if defined?(Reactor)
+      Ractor.current[:__did_you_mean_formatter__] || Formatter
+    else
+      Formatter
+    end
   end
 
   # Updates the primary formatter used to format the suggestions.
   def self.formatter=(formatter)
-    @formatter = formatter
+    if defined?(Reactor)
+      Ractor.current[:__did_you_mean_formatter__] = formatter
+    end
   end
-
-  @formatter = Formatter.new
 end
diff --git a/lib/did_you_mean/core_ext/name_error.rb b/lib/did_you_mean/core_ext/name_error.rb
index 7e99282b41..eb3ef117a0 100644
--- a/lib/did_you_mean/core_ext/name_error.rb
+++ b/lib/did_you_mean/core_ext/name_error.rb
@@ -26,7 +26,7 @@ module DidYouMean
     end
 
     def spell_checker
-      SPELL_CHECKERS[self.class.to_s].new(self)
+      DidYouMean.spell_checkers[self.class.to_s].new(self)
     end
   end
 end
diff --git a/lib/did_you_mean/formatter.rb b/lib/did_you_mean/formatter.rb
index 01eb59100a..02c0bc75d3 100644
--- a/lib/did_you_mean/formatter.rb
+++ b/lib/did_you_mean/formatter.rb
@@ -26,7 +26,7 @@ module DidYouMean
     #
     #   # => nil
     #
-    def message_for(corrections)
+    def self.message_for(corrections)
       corrections.empty? ? "" : "\nDid you mean?  #{corrections.join("\n               ")}"
     end
   end
diff --git a/lib/did_you_mean/spell_checkers/method_name_checker.rb b/lib/did_you_mean/spell_checkers/method_name_checker.rb
index 0483127d6f..d8ebaa4616 100644
--- a/lib/did_you_mean/spell_checkers/method_name_checker.rb
+++ b/lib/did_you_mean/spell_checkers/method_name_checker.rb
@@ -6,6 +6,7 @@ module DidYouMean
 
     NAMES_TO_EXCLUDE = { NilClass => nil.methods }
     NAMES_TO_EXCLUDE.default = []
+    Ractor.make_shareable(NAMES_TO_EXCLUDE) if defined?(Ractor)
 
     # +MethodNameChecker::RB_RESERVED_WORDS+ is the list of reserved words in
     # Ruby that take an argument. Unlike
@@ -36,6 +37,8 @@ module DidYouMean
       yield
     )
 
+    Ractor.make_shareable(RB_RESERVED_WORDS) if defined?(Ractor)
+
     def initialize(exception)
       @method_name  = exception.name
       @receiver     = exception.receiver
diff --git a/lib/did_you_mean/spell_checkers/name_error_checkers/variable_name_checker.rb b/lib/did_you_mean/spell_checkers/name_error_checkers/variable_name_checker.rb
index 3e51b4fa3a..36d00349c6 100644
--- a/lib/did_you_mean/spell_checkers/name_error_checkers/variable_name_checker.rb
+++ b/lib/did_you_mean/spell_checkers/name_error_checkers/variable_name_checker.rb
@@ -8,6 +8,7 @@ module DidYouMean
 
     NAMES_TO_EXCLUDE = { 'foo' => [:fork, :for] }
     NAMES_TO_EXCLUDE.default = []
+    Ractor.make_shareable(NAMES_TO_EXCLUDE) if defined?(Ractor)
 
     # +VariableNameChecker::RB_RESERVED_WORDS+ is the list of all reserved
     # words in Ruby. They could be declared like methods are, and a typo would
@@ -62,6 +63,8 @@ module DidYouMean
       __ENCODING__
     )
 
+    Ractor.make_shareable(RB_RESERVED_WORDS) if defined?(Ractor)
+
     def initialize(exception)
       @name       = exception.name.to_s.tr("@", "")
       @lvar_names = exception.respond_to?(:local_variables) ? exception.local_variables : []
diff --git a/lib/did_you_mean/spell_checkers/require_path_checker.rb b/lib/did_you_mean/spell_checkers/require_path_checker.rb
index e4cdb9f43d..586ced37de 100644
--- a/lib/did_you_mean/spell_checkers/require_path_checker.rb
+++ b/lib/did_you_mean/spell_checkers/require_path_checker.rb
@@ -9,7 +9,10 @@ module DidYouMean
     attr_reader :path
 
     INITIAL_LOAD_PATH = $LOAD_PATH.dup.freeze
-    ENV_SPECIFIC_EXT  = ".#{RbConfig::CONFIG["DLEXT"]}"
+    Ractor.make_shareable(INITIAL_LOAD_PATH) if defined?(Ractor)
+
+    ENV_SPECIFIC_EXT = ".#{RbConfig::CONFIG["DLEXT"]}"
+    Ractor.make_shareable(ENV_SPECIFIC_EXT) if defined?(Ractor)
 
     private_constant :INITIAL_LOAD_PATH, :ENV_SPECIFIC_EXT
 
diff --git a/lib/did_you_mean/version.rb b/lib/did_you_mean/version.rb
index 8df73e1d62..bf8f795f10 100644
--- a/lib/did_you_mean/version.rb
+++ b/lib/did_you_mean/version.rb
@@ -1,3 +1,3 @@
 module DidYouMean
-  VERSION = "1.6.0-alpha"
+  VERSION = "1.6.0".freeze
 end
diff --git a/test/did_you_mean/core_ext/test_name_error_extension.rb b/test/did_you_mean/core_ext/test_name_error_extension.rb
index 9dc08dbde3..91871cda9a 100644
--- a/test/did_you_mean/core_ext/test_name_error_extension.rb
+++ b/test/did_you_mean/core_ext/test_name_error_extension.rb
@@ -1,7 +1,7 @@
 require_relative '../helper'
 
 class NameErrorExtensionTest < Test::Unit::TestCase
-  SPELL_CHECKERS = DidYouMean::SPELL_CHECKERS
+  SPELL_CHECKERS = DidYouMean.spell_checkers
 
   class TestSpellChecker
     def initialize(*); end
@@ -9,13 +9,14 @@ class NameErrorExtensionTest < Test::Unit::TestCase
   end
 
   def setup
-    @org, SPELL_CHECKERS['NameError'] = SPELL_CHECKERS['NameError'], TestSpellChecker
+    @original_spell_checker = DidYouMean.spell_checkers['NameError']
+    DidYouMean.correct_error(NameError, TestSpellChecker)
 
     @error = assert_raise(NameError){ doesnt_exist }
   end
 
   def teardown
-    SPELL_CHECKERS['NameError'] = @org
+    DidYouMean.correct_error(NameError, @original_spell_checker)
   end
 
   def test_message
diff --git a/test/did_you_mean/helper.rb b/test/did_you_mean/helper.rb
index d8aa41c3d1..7cb7b10282 100644
--- a/test/did_you_mean/helper.rb
+++ b/test/did_you_mean/helper.rb
@@ -4,6 +4,10 @@ module DidYouMean
   module TestHelper
     class << self
       attr_reader :root
+
+      def ractor_compatible?
+        defined?(Ractor) && RUBY_VERSION >= "3.1.0"
+      end
     end
 
     if File.file?(File.expand_path('../lib/did_you_mean.rb', __dir__))
diff --git a/test/did_you_mean/test_ractor_compatibility.rb b/test/did_you_mean/test_ractor_compatibility.rb
new file mode 100644
index 0000000000..2970793e3f
--- /dev/null
+++ b/test/did_you_mean/test_ractor_compatibility.rb
@@ -0,0 +1,102 @@
+return if not DidYouMean::TestHelper.ractor_compatible?
+
+require_relative './helper'
+
+class RactorCompatibilityTest < Test::Unit::TestCase
+  include DidYouMean::TestHelper
+
+  class ::Book; end
+  class FirstNameError < NameError; end
+
+  def test_class_name_suggestion_works_in_ractor
+    error = Ractor.new {
+              begin
+                Boook
+              rescue NameError => e
+                e.corrections # It is important to call the #corrections method within Ractor.
+                e
+              end
+            }.take
+
+    assert_correction "Book", error.corrections
+  end
+
+  def test_key_name_suggestion_works_in_ractor
+    error = Ractor.new {
+              begin
+                hash = { "foo" => 1, bar: 2 }
+
+                hash.fetch(:bax)
+              rescue KeyError => e
+                e.corrections # It is important to call the #corrections method within Ractor.
+                e
+              end
+            }.take
+
+    assert_correction ":bar", error.corrections
+    assert_match "Did you mean?  :bar", error.to_s
+  end
+
+  def test_method_name_suggestion_works_in_ractor
+    error = Ractor.new {
+              begin
+                self.to__s
+              rescue NoMethodError => e
+                e.corrections # It is important to call the #corrections method within Ractor.
+                e
+              end
+            }.take
+
+    assert_correction :to_s, error.corrections
+    assert_match "Did you mean?  to_s",  error.to_s
+  end
+
+  if defined?(::NoMatchingPatternKeyError)
+    def test_pattern_key_name_suggestion_works_in_ractor
+      error = Ractor.new {
+                begin
+                  eval(<<~RUBY, binding, __FILE__, __LINE__)
+                          hash = {foo: 1, bar: 2, baz: 3}
+                          hash => {fooo:}
+                          fooo = 1 # suppress "unused variable: fooo" warning
+                  RUBY
+                rescue NoMatchingPatternKeyError => e
+                  e.corrections # It is important to call the #corrections method within Ractor.
+                  e
+                end
+              }.take
+
+      assert_correction ":foo", error.corrections
+      assert_match "Did you mean?  :foo", error.to_s
+    end
+  end
+
+  def test_can_raise_other_name_error_in_ractor
+    error = Ractor.new {
+      begin
+        raise FirstNameError, "Other name error"
+      rescue FirstNameError => e
+        e.corrections # It is important to call the #corrections method within Ractor.
+        e
+      end
+    }.take
+
+    assert_not_match(/Did you mean\?/, error.message)
+  end
+
+  def test_variable_name_suggestion_works_in_ractor
+    error = Ractor.new {
+      in_ractor = in_ractor = 1
+
+      begin
+        in_reactor
+      rescue NameError => e
+        e.corrections # It is important to call the #corrections method within Ractor.
+        e
+      end
+    }.take
+
+    assert_correction :in_ractor, error.corrections
+    assert_match "Did you mean?  in_ractor", error.to_s
+  end
+end