In this study, a class activity was developed and conducted directing Japanese university students (“readers”) to comment on the Japanese language learners’ (“writers”) opinion essays to enhance the writers’ ability to convey ideas through written communication as well as their awareness of actual readers outside the classroom. The readers commented on the writers’ mastery of critical essay elements such as persuasiveness, accepting counterarguments, and setting the argument scope; the writers then applied the readers’ comments to their revisions. Most learners responded positively to the peer-based critiques and said the activity increased their confidence and intrinsic motivation to write.