Online peer feedback has become prevalent in university writing classes due to the widespread use of peer learning technology. This paper reports an exploratory study of Chinese-speaking undergraduate students' experiences of receiving and reflecting on online peer feedback for text revision in an English as a second language (L2) writing classroom at a northeastern-Chinese university. Twelve students were recruited from an in-person writing class taught in English by a Chinese-speaking instructor and asked to write and revise their English persuasive essays. The students sought online peer feedback asynchronously using an instant messaging platform (QQ), completed the revision worksheet that involved coding and reflecting on the peer feedback received, and wrote second drafts. Data included students' first and second drafts, online peer feedback, analytic writing rubrics, revision worksheets, and semi-structured interviews. The quantitative analysis of students writing performance indicated that peer feedback led to students' revisions produced meaningful improvements in the scores between drafts. The results of qualitative analyses suggested that: (1) the primary focus of peer feedback was content; (2) students generally followed peer feedback, but ignored disagreements with their peers; (3) students strategically asked for clarification from peers on the QQ platform when feedback was unclear or confusing while collecting information from the internet, e-dictionaries, and Grammarly; and (4) students thought they benefited from experiencing the peer-mediated revision process. Based on the results, we provide recommendations and instructional guidance for university writing instructors for scaffolding L2 students' text revision practices through receiving and reflecting on online peer feedback.