Online written corrective feedback via Google Docs, in recent years, has been used and brought about positive outcomes in different teaching contexts. In this light, this study was conducted to examine the different effects between teacher feedback using Google Docs and the combined peer feedback and teacher feedback using Google Docs on EFL high school students’ performance in writing paragraphs. The study also attempted to gain insights into students’ attitudes towards the effect of peer feedback and teacher feedback using Google Docs on their paragraph writing. In this study, a mixed research method was employed; both quantitative and qualitative data were collected. Twenty two grade 11 students in a high school in the Mekong Delta of Vietnam were selected as participants. They were assigned to two groups of treatment: the experimental group, receiving both peer feedback and teacher feedback using Google Docs and the control group who only received teacher feedback using Google Docs. Participants completed two writing tasks; each of them included first draft, second draft and final draft. Prior to the study, students from the experimental group received a face-to-face training on giving peer feedback. Data were collected from six drafts of two writing tasks, three drafts for one task, and interviews at the end of the study. Results indicated that participants who received teacher feedback in the control group performed their paragraph writing better than those receiving both peer feedback and teacher feedback using Google Docs in the experimental group after the study. Also, participants in both groups improved their writing performance in their revised drafts. From the interviews, results showed participants’ positive attitudes towards the impact of peer feedback and teacher feedback using Google Docs on their paragraph writing.