diff --git a/lib/rspec/core.rb b/lib/rspec/core.rb
index aecbecfe01..3c1e489649 100644
--- a/lib/rspec/core.rb
+++ b/lib/rspec/core.rb
@@ -12,7 +12,6 @@
   warnings
 
   set
-  flat_map
   filter_manager
   dsl
   notifications
diff --git a/lib/rspec/core/configuration.rb b/lib/rspec/core/configuration.rb
index 15f3dee4a2..5d98a4b87d 100644
--- a/lib/rspec/core/configuration.rb
+++ b/lib/rspec/core/configuration.rb
@@ -2154,7 +2154,7 @@ def run_suite_hooks(hook_description, hooks)
       end
 
       def get_files_to_run(paths)
-        files = FlatMap.flat_map(paths_to_check(paths)) do |path|
+        files = paths_to_check(paths).flat_map do |path|
           path = path.gsub(File::ALT_SEPARATOR, File::SEPARATOR) if File::ALT_SEPARATOR
           File.directory?(path) ? gather_directories(path) : extract_location(path)
         end.uniq
diff --git a/lib/rspec/core/configuration_options.rb b/lib/rspec/core/configuration_options.rb
index f669cda5f9..4e74719eb6 100644
--- a/lib/rspec/core/configuration_options.rb
+++ b/lib/rspec/core/configuration_options.rb
@@ -169,7 +169,7 @@ def parse_args_ignoring_files_or_dirs_to_run(args, source)
       def args_from_options_file(path)
         return [] unless path && File.exist?(path)
         config_string = options_file_as_erb_string(path)
-        FlatMap.flat_map(config_string.split(/\n+/), &:shellsplit)
+        config_string.split(/\n+/).flat_map(&:shellsplit)
       end
 
       def options_file_as_erb_string(path)
diff --git a/lib/rspec/core/example_group.rb b/lib/rspec/core/example_group.rb
index 1f4f4b07dc..766395797f 100644
--- a/lib/rspec/core/example_group.rb
+++ b/lib/rspec/core/example_group.rb
@@ -459,7 +459,7 @@ def self.filtered_examples
       # @private
       def self.descendant_filtered_examples
         @descendant_filtered_examples ||= filtered_examples +
-          FlatMap.flat_map(children, &:descendant_filtered_examples)
+          children.flat_map(&:descendant_filtered_examples)
       end
 
       # @private
@@ -501,7 +501,7 @@ def self.next_runnable_index_for(file)
 
       # @private
       def self.descendants
-        @_descendants ||= [self] + FlatMap.flat_map(children, &:descendants)
+        @_descendants ||= [self] + children.flat_map(&:descendants)
       end
 
       ## @private
@@ -646,7 +646,7 @@ def self.for_filtered_examples(reporter, &block)
       def self.declaration_locations
         @declaration_locations ||= [Metadata.location_tuple_from(metadata)] +
           examples.map { |e| Metadata.location_tuple_from(e.metadata) } +
-          FlatMap.flat_map(children, &:declaration_locations)
+          children.flat_map(&:declaration_locations)
       end
 
       # @return [String] the unique id of this example group. Pass
diff --git a/lib/rspec/core/flat_map.rb b/lib/rspec/core/flat_map.rb
deleted file mode 100644
index dd294ae84d..0000000000
--- a/lib/rspec/core/flat_map.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-module RSpec
-  module Core
-    # @private
-    module FlatMap
-      def flat_map(array, &block)
-        array.flat_map(&block)
-      end
-
-      module_function :flat_map
-    end
-  end
-end
diff --git a/lib/rspec/core/formatters/exception_presenter.rb b/lib/rspec/core/formatters/exception_presenter.rb
index 062b14f8fe..6ebc420d4a 100644
--- a/lib/rspec/core/formatters/exception_presenter.rb
+++ b/lib/rspec/core/formatters/exception_presenter.rb
@@ -334,7 +334,7 @@ def sub_failure_list_formatter(exception, message_color)
             common_backtrace_truncater = CommonBacktraceTruncater.new(exception)
 
             lambda do |failure_number, colorizer|
-              FlatMap.flat_map(exception.all_exceptions.each_with_index) do |failure, index|
+              exception.all_exceptions.each_with_index.flat_map do |failure, index|
                 options = with_multiple_error_options_as_needed(
                   failure,
                   :description             => nil,
diff --git a/lib/rspec/core/formatters/snippet_extractor.rb b/lib/rspec/core/formatters/snippet_extractor.rb
index 6b7102de81..caee4d4dce 100644
--- a/lib/rspec/core/formatters/snippet_extractor.rb
+++ b/lib/rspec/core/formatters/snippet_extractor.rb
@@ -70,7 +70,7 @@ def line_range_of_expression
           end
 
           def unclosed_tokens_in_line_range(line_range)
-            tokens = FlatMap.flat_map(line_range) do |line_number|
+            tokens = line_range.flat_map do |line_number|
               source.tokens_by_line_number[line_number]
             end
 
diff --git a/lib/rspec/core/hooks.rb b/lib/rspec/core/hooks.rb
index 8d1ea5f5ec..d69e2fe63f 100644
--- a/lib/rspec/core/hooks.rb
+++ b/lib/rspec/core/hooks.rb
@@ -564,7 +564,7 @@ def process(host, parent_groups, globals, position, scope)
           hooks_to_process = globals.processable_hooks_for(position, scope, host)
           return if hooks_to_process.empty?
 
-          hooks_to_process -= FlatMap.flat_map(parent_groups) do |group|
+          hooks_to_process -= parent_groups.flat_map do |group|
             group.hooks.all_hooks_for(position, scope)
           end
           return if hooks_to_process.empty?
@@ -609,7 +609,7 @@ def run_example_hooks_for(example, position, each_method)
         end
 
         def run_around_example_hooks_for(example)
-          hooks = FlatMap.flat_map(owner_parent_groups) do |group|
+          hooks = owner_parent_groups.flat_map do |group|
             group.hooks.matching_hooks_for(:around, :example, example)
           end
 
diff --git a/lib/rspec/core/world.rb b/lib/rspec/core/world.rb
index 108af900a6..d4b338ea93 100644
--- a/lib/rspec/core/world.rb
+++ b/lib/rspec/core/world.rb
@@ -99,18 +99,18 @@ def exclusion_filter
       #
       # Get count of examples to be run.
       def example_count(groups=example_groups)
-        FlatMap.flat_map(groups) { |g| g.descendants }.
+        groups.flat_map { |g| g.descendants }.
           inject(0) { |a, e| a + e.filtered_examples.size }
       end
 
       # @private
       def all_example_groups
-        FlatMap.flat_map(example_groups) { |g| g.descendants }
+        example_groups.flat_map { |g| g.descendants }
       end
 
       # @private
       def all_examples
-        FlatMap.flat_map(all_example_groups) { |g| g.examples }
+        all_example_groups.flat_map { |g| g.examples }
       end
 
       # @private
@@ -223,7 +223,7 @@ def announce_exclusion_filter(announcements)
 
       def descending_declaration_line_numbers_by_file
         @descending_declaration_line_numbers_by_file ||= begin
-          declaration_locations = FlatMap.flat_map(example_groups, &:declaration_locations)
+          declaration_locations = example_groups.flat_map(&:declaration_locations)
 
           declarations_by_file = declaration_locations.group_by(&:first) # by file name
 
diff --git a/spec/rspec/core/configuration_spec.rb b/spec/rspec/core/configuration_spec.rb
index e49aafd615..4b0207e8e1 100644
--- a/spec/rspec/core/configuration_spec.rb
+++ b/spec/rspec/core/configuration_spec.rb
@@ -1982,7 +1982,7 @@ def exclude?(line)
         registered_examples = nil
 
         RSpec.configuration.define_derived_metadata(:ex) do |_meta|
-          registered_examples = FlatMap.flat_map(RSpec.world.all_example_groups, &:examples)
+          registered_examples = RSpec.world.all_example_groups.flat_map(&:examples)
         end
 
         example = nil