diff --git a/lib/rubygems.rb b/lib/rubygems.rb
index 762ecdf857..ddadd0f797 100644
--- a/lib/rubygems.rb
+++ b/lib/rubygems.rb
@@ -788,7 +788,7 @@ An Array (#{env.inspect}) was passed in from #{caller[3]}
 
   def self.open_with_flock(path, flags, &block)
     File.open(path, flags) do |io|
-      unless java_platform?
+      if !java_platform? && !solaris_platform?
         begin
           io.flock(File::LOCK_EX)
         rescue Errno::ENOSYS, Errno::ENOTSUP
@@ -1015,6 +1015,13 @@ An Array (#{env.inspect}) was passed in from #{caller[3]}
     RUBY_PLATFORM == "java"
   end
 
+  ##
+  # Is this platform Solaris?
+
+  def self.solaris_platform?
+    RUBY_PLATFORM =~ /solaris/
+  end
+
   ##
   # Load +plugins+ as Ruby files