diff --git a/lib/rubocop/target_finder.rb b/lib/rubocop/target_finder.rb
index e9787260f86..2655ac71ce6 100644
--- a/lib/rubocop/target_finder.rb
+++ b/lib/rubocop/target_finder.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require 'set'
-require 'open3'
 
 module RuboCop
   # This class finds target files to inspect by scanning the directory tree
@@ -60,13 +59,10 @@ def target_files_in_dir(base_dir = Dir.pwd)
       end
       all_files = find_files(base_dir, File::FNM_DOTMATCH)
       hidden_files = Set.new(all_files - find_files(base_dir, 0))
-
-      git_files = ls_git_files(base_dir)
-
       base_dir_config = @config_store.for(base_dir)
 
       target_files = all_files.select do |file|
-        to_inspect?(file, git_files, hidden_files, base_dir_config)
+        to_inspect?(file, hidden_files, base_dir_config)
       end
 
       # Most recently modified file first.
@@ -75,6 +71,13 @@ def target_files_in_dir(base_dir = Dir.pwd)
       target_files
     end
 
+    def to_inspect?(file, hidden_files, base_dir_config)
+      return false if base_dir_config.file_to_exclude?(file)
+      return true if !hidden_files.include?(file) && ruby_file?(file)
+
+      base_dir_config.file_to_include?(file)
+    end
+
     # Search for files recursively starting at the given base directory using
     # the given flags that determine how the match is made. Excluded files will
     # be removed later by the caller, but as an optimization find_files removes
@@ -97,31 +100,6 @@ def find_files(base_dir, flags)
       Dir.glob(pattern, flags).select { |path| FileTest.file?(path) }
     end
 
-    private
-
-    def ls_git_files(base_dir)
-      return if `sh -c 'command -v git'`.empty?
-
-      output, _error, status = Open3.capture3(
-        'git', 'ls-files', '-z', base_dir,
-        '--exclude-standard', '--others', '--cached', '--modified'
-      )
-
-      return unless status.success?
-
-      output.split("\0").map { |git_file| "#{base_dir}/#{git_file}" }
-    end
-
-    def to_inspect?(file, git_files, hidden_files, base_dir_config)
-      return false if base_dir_config.file_to_exclude?(file)
-
-      if !hidden_files.include?(file) && ruby_file?(file)
-        return git_files.nil? || git_files.include?(file)
-      end
-
-      base_dir_config.file_to_include?(file)
-    end
-
     def toplevel_dirs(base_dir, flags)
       Dir.glob(File.join(base_dir, '*'), flags).select do |dir|
         File.directory?(dir) && !dir.end_with?('/.', '/..')
diff --git a/manual/configuration.md b/manual/configuration.md
index 8b079ef6d9d..aeb2ba9e877 100644
--- a/manual/configuration.md
+++ b/manual/configuration.md
@@ -229,7 +229,6 @@ ruby interpreters listed under `AllCops`/`RubyInterpreters` are
 inspected, unless the file also matches a pattern in
 `AllCops`/`Exclude`. Hidden directories (i.e., directories whose names
 start with a dot) are not searched by default.
-Files ignored by Git are ignored by RuboCop by default.
 
 Here is an example that might be used for a Rails project:
 
diff --git a/spec/rubocop/target_finder_spec.rb b/spec/rubocop/target_finder_spec.rb
index 1b4d5a79a15..920c8db7c4d 100644
--- a/spec/rubocop/target_finder_spec.rb
+++ b/spec/rubocop/target_finder_spec.rb
@@ -398,65 +398,6 @@
       expect(found_basenames).not_to include('ruby2.rb')
     end
 
-    context 'in git repo directory' do
-      before do
-        system 'git init'
-
-        create_empty_file('git_regular.rb')
-        create_empty_file('git_group.rb')
-        create_empty_file('git_excluded.rb')
-        create_empty_file('git_glob.rb')
-        create_empty_file('git with spaces.rb')
-        create_empty_file('git_dir/thing.rb')
-        create_file('.gitignore', <<-'CONTENT'.strip_indent)
-          git_regular.rb
-          git_gr[ao]up.rb
-          !git_excluded.rb
-          git_glob*
-          git_dir/
-        CONTENT
-      end
-
-      it 'does not pick files ignored by git' do
-        expect(found_basenames).not_to include(
-          'git_regular.rb',
-          'git_group.rb',
-          'git_glob.rb',
-          'git_dir/thing.rb'
-        )
-        expect(found_basenames).to include(
-          'git_excluded.rb',
-          'git with spaces.rb'
-        )
-      end
-
-      context 'without `git` executable' do
-        before do
-          allow_any_instance_of(Kernel).to receive(:`)
-            .with(/command -v git/)
-            .and_return('')
-
-          allow_any_instance_of(Kernel).to receive(:`)
-            .with(start_with('git ls-files'))
-            .and_raise(Errno::ENOENT, 'git')
-        end
-
-        it 'does not fail' do
-          expect { found_basenames }.not_to raise_error
-        end
-      end
-
-      context 'with `*` in argument' do
-        let(:base_dir) { './git*' }
-
-        it 'does not fail' do
-          expect(found_basenames).not_to include(
-            'thing.rb'
-          )
-        end
-      end
-    end
-
     context 'when an exception is raised while reading file' do
       around do |example|
         original_stderr = $stderr