diff --git a/config/flay.yml b/config/flay.yml
index 3c2258be..c8a9cc0b 100644
--- a/config/flay.yml
+++ b/config/flay.yml
@@ -1,3 +1,3 @@
 ---
 threshold: 18
-total_score: 1208
+total_score: 1213
diff --git a/config/reek.yml b/config/reek.yml
index 76628b8a..3e437d9a 100644
--- a/config/reek.yml
+++ b/config/reek.yml
@@ -131,6 +131,7 @@ UtilityFunction:
   - Mutant::Integration::Rspec#parse_example
   - Mutant::Meta::Example::Verification#format_mutation
   - Mutant::Repository::Diff#tracks? # intentional, private
+  - Mutant::Repository::Diff#within_working_directory? # intentional, private
   - Mutant::Reporter::CLI::Format::Progressive#new_buffer
   - Mutant::Reporter::CLI::Printer::StatusProgressive#object # False positive calls super
   - Mutant::Integration::Rspec#parse_expression # intentional, private
diff --git a/lib/mutant/repository.rb b/lib/mutant/repository.rb
index 6b230e68..16647424 100644
--- a/lib/mutant/repository.rb
+++ b/lib/mutant/repository.rb
@@ -48,7 +48,7 @@ module Mutant
       #
       # @api private
       def touches?(path, line_range)
-        return false unless tracks?(path)
+        return false unless within_working_directory?(path) && tracks?(path)
 
         command = %W[
           git log
@@ -83,6 +83,18 @@ module Mutant
         )
       end
 
+      # Test if the path is within the current working directory
+      #
+      # @param [Pathname] path
+      #
+      # @return [TrueClass, nil]
+      #
+      # @api private
+      def within_working_directory?(path)
+        working_directory = Pathname.pwd
+        path.ascend { |parent| return true if working_directory.eql?(parent) }
+      end
+
     end # Diff
   end # Repository
 end # Mutant
diff --git a/spec/unit/mutant/repository/diff_spec.rb b/spec/unit/mutant/repository/diff_spec.rb
index 92b53d40..e394b694 100644
--- a/spec/unit/mutant/repository/diff_spec.rb
+++ b/spec/unit/mutant/repository/diff_spec.rb
@@ -8,25 +8,39 @@ describe Mutant::Repository::Diff do
   end
 
   describe '#touches?' do
-    let(:object)        { described_class.new('from_rev', 'to_rev') }
-    let(:path)          { Pathname.new('foo.rb')                    }
-    let(:line_range)    { 1..2                                      }
+    let(:object)     { described_class.new('from_rev', 'to_rev') }
+    let(:path)       { Pathname.pwd.join('foo.rb')               }
+    let(:line_range) { 1..2                                      }
 
     subject { object.touches?(path, line_range) }
 
-    before do
-      expect(Kernel).to receive(:system)
-        .ordered
-        .with(
-          *%w[git ls-files --error-unmatch -- foo.rb],
-          out: File::NULL,
-          err: File::NULL
-        ).and_return(git_ls_success?)
+    shared_context 'test if git tracks the file' do
+      before do
+        expect(Kernel).to receive(:system)
+          .ordered
+          .with(
+            *%W[git ls-files --error-unmatch -- #{path}],
+            out: File::NULL,
+            err: File::NULL
+          ).and_return(git_ls_success?)
+      end
+    end
+
+    context 'when file is in a different subdirectory' do
+      let(:path) { Pathname.new('/foo.rb') }
+
+      before do
+        expect(Kernel).to_not receive(:system)
+      end
+
+      it { should be(false) }
     end
 
     context 'when file is NOT tracked in repository' do
       let(:git_ls_success?) { false }
 
+      include_context 'test if git tracks the file'
+
       it { should be(false) }
     end
 
@@ -36,6 +50,8 @@ describe Mutant::Repository::Diff do
       let(:stdout)          { double('Stdout', empty?: stdout_empty?) }
       let(:stdout_empty?)   { false                                   }
 
+      include_context 'test if git tracks the file'
+
       before do
         expect(Open3).to receive(:capture2)
           .ordered
@@ -44,9 +60,7 @@ describe Mutant::Repository::Diff do
       end
 
       let(:expected_git_log_command) do
-        %w[
-          git log from_rev...to_rev -L 1,2:foo.rb
-        ]
+        %W[git log from_rev...to_rev -L 1,2:#{path}]
       end
 
       context 'on failure of git log command' do