diff --git a/configure.ac b/configure.ac
index 098b6ca..21ab733 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,6 +37,11 @@
                            Default = "/usr/local/lib"])
 AS_IF([test "x$JAVA_PREFIX" = x], [JAVA_PREFIX="/usr/local/lib"])
 
+AC_ARG_VAR([RUBY_PREFIX], [Prefix for installing Ruby modules.
+                           (Normal --prefix is ignored for Ruby because
+                           Ruby has different conventions.)
+                           Default = none, let ruby setup decide])
+
 AC_ARG_VAR([PHP_PREFIX], [Prefix for installing PHP modules.
                          (Normal --prefix is ignored for PHP because
                          PHP has different conventions.)
diff --git a/lib/rb/Makefile.am b/lib/rb/Makefile.am
index 9cfffc7..da45ed5 100644
--- a/lib/rb/Makefile.am
+++ b/lib/rb/Makefile.am
@@ -29,7 +29,7 @@
 	spec
 
 all-local:
-	$(RUBY) setup.rb config
+	if [ -n "$(RUBY_PREFIX)" ] ; then $(RUBY) setup.rb config --prefix=$(DESTDIR)$(RUBY_PREFIX) --rbdir='$$libdir/ruby' --sodir='$$libdir/ruby' ; elif [ -n "$(DESTDIR)" ] ; then $(RUBY) setup.rb config --prefix=$(DESTDIR) ; else $(RUBY) setup.rb config ; fi
 	$(RUBY) setup.rb setup
 
 install-exec-hook: