diff --git a/lib/rake/task.rb b/lib/rake/task.rb
index 1d3244d2b..5300b6fc4 100644
--- a/lib/rake/task.rb
+++ b/lib/rake/task.rb
@@ -304,10 +304,10 @@ def transform_comments(separator, &block)
     private :transform_comments
 
     # Get the first sentence in a string. The sentence is terminated
-    # by the first period or the end of the line. Decimal points do
-    # not count as periods.
+    # by the first period, exclamation mark, or the end of the line.
+    # Decimal points do not count as periods.
     def first_sentence(string)
-      string.split(/\.[ \t]|\.$|\n/).first
+      string.split(/(?<=\w)(\.|!)[ \t]|(\.$|!)|\n/).first
     end
     private :first_sentence
 
diff --git a/test/test_rake_task.rb b/test/test_rake_task.rb
index 63ff86556..d9e13bd60 100644
--- a/test/test_rake_task.rb
+++ b/test/test_rake_task.rb
@@ -352,12 +352,24 @@ def test_comment_setting
     assert_equal "A Comment", t.comment
   end
 
-  def test_comments_with_sentences
+  def test_comments_with_sentences_period
     desc "Comment 1. Comment 2."
     t = task(:t, :name, :rev)
     assert_equal "Comment 1", t.comment
   end
 
+  def test_comments_with_sentences_exclamation_mark
+    desc "An exclamation mark! Comment."
+    t = task(:t, :name, :rev)
+    assert_equal "An exclamation mark", t.comment
+  end
+
+  def test_comments_with_many_periods
+    desc "This is a test...I think ... testing. Comment."
+    t = task(:t, :name, :rev)
+    assert_equal "This is a test...I think ... testing", t.comment
+  end
+
   def test_comments_with_tabbed_sentences
     desc "Comment 1.\tComment 2."
     t = task(:t, :name, :rev)