diff --git a/ext/extconf.rb b/ext/extconf.rb
index 9a9b0208b..160d08c34 100644
--- a/ext/extconf.rb
+++ b/ext/extconf.rb
@@ -139,6 +139,15 @@ def manual_ssl_config
 when /aix/
   CONFIG['LDSHARED'] = "$(CXX) -shared -Wl,-G -Wl,-brtl"
 
+when /cygwin/
+  # For rubies built with Cygwin, CXX may be set to CC, which is just
+  # a wrapper for gcc.
+  # This will compile, but it will not link to the C++ std library.
+  # Explicitly set CXX to use g++.
+  CONFIG['CXX'] = "g++"
+  # on Unix we need a g++ link, not gcc.
+  CONFIG['LDSHARED'] = "$(CXX) -shared"
+
 else
   # on Unix we need a g++ link, not gcc.
   CONFIG['LDSHARED'] = "$(CXX) -shared"
diff --git a/ext/fastfilereader/extconf.rb b/ext/fastfilereader/extconf.rb
index 1c9b1b2af..07fe97905 100644
--- a/ext/fastfilereader/extconf.rb
+++ b/ext/fastfilereader/extconf.rb
@@ -77,6 +77,15 @@ def add_define(name)
   # on Unix we need a g++ link, not gcc.
   CONFIG['LDSHARED'] = "$(CXX) -shared -Wl,-G"
 
+when /cygwin/
+  # For rubies built with Cygwin, CXX may be set to CC, which is just
+  # a wrapper for gcc.
+  # This will compile, but it will not link to the C++ std library.
+  # Explicitly set CXX to use g++.
+  CONFIG['CXX'] = "g++"
+  # on Unix we need a g++ link, not gcc.
+  CONFIG['LDSHARED'] = "$(CXX) -shared"
+
 else
   # on Unix we need a g++ link, not gcc.
   CONFIG['LDSHARED'] = "$(CXX) -shared"