diff --git a/setup.py b/setup.py
index 4d3f081..d3d8d42 100644
--- a/setup.py
+++ b/setup.py
@@ -783,9 +783,13 @@ class PyBuildExt(build_ext):
         exts.append( Extension('_csv', ['_csv.c']) )
 
         # socket(2)
+        if host_platform == 'sunos5':
+           socket_libs = ['socket', 'nsl']
+        else:
+           socket_libs = []
         exts.append( Extension('_socket', ['socketmodule.c', 'timemodule.c'],
                                depends=['socketmodule.h'],
-                               libraries=math_libs) )
+                               libraries=math_libs + socket_libs) )
         # Detect SSL support for the socket module (via _ssl)
         search_for_ssl_incs_in = [
                               '/usr/local/ssl/include',