diff --git a/lib/prism/translation/ruby_parser.rb b/lib/prism/translation/ruby_parser.rb
index a33ea2306c..1fb0e27846 100644
--- a/lib/prism/translation/ruby_parser.rb
+++ b/lib/prism/translation/ruby_parser.rb
@@ -4,7 +4,7 @@
 begin
   require "sexp"
 rescue LoadError
-  warn(%q{Error: Unable to load sexp. Add `gem "sexp"` to your Gemfile.})
+  warn(%q{Error: Unable to load sexp. Add `gem "sexp_processor"` to your Gemfile.})
   exit(1)
 end