diff --git a/lib/jsduck/type_parser.rb b/lib/jsduck/type_parser.rb
index f38fcd502ed1bc0d5d77fe4e0b8c529f89ca84a7..7763574ee4f115be9941944f1a374bdb65a33402 100644
--- a/lib/jsduck/type_parser.rb
+++ b/lib/jsduck/type_parser.rb
@@ -158,7 +158,7 @@ module JsDuck
         return false unless function_type
       elsif @input.check(/['"]/)
         return false unless string_literal
-      elsif @input.check(/\d/)
+      elsif @input.check(/[\d-]/)
         return false unless number_literal
       else
         return false unless type_name
@@ -305,10 +305,10 @@ module JsDuck
     end
 
     #
-    #     <number-literal> ::= <digit>+ [ "." <digit>+ ]
+    #     <number-literal> ::= [ "-" ] <digit>+ [ "." <digit>+ ]
     #
     def number_literal
-      @out << @input.scan(/\d+(\.\d+)?/)
+      @out << @input.scan(/-?\d+(\.\d+)?/)
 
       true
     end
diff --git a/spec/type_parser_spec.rb b/spec/type_parser_spec.rb
index fd814e8d9dac6fa71a098e653bc59ff27e2d59db..35435a99f42683ccc0401d8174569cbd1b3ca1b5 100644
--- a/spec/type_parser_spec.rb
+++ b/spec/type_parser_spec.rb
@@ -34,6 +34,10 @@ describe JsDuck::TypeParser do
     parse('42').should == true
   end
 
+  it "matches negative number literal" do
+    parse('-6').should == true
+  end
+
   it "matches float number literal" do
     parse('3.14').should == true
   end