This study investigates the quality of peer-generated feedback and AI-generated feedback (specifically from ChatGPT) in the context of essay writing. It compares the effectiveness of these two feedback sources in enhancing students' writing skills. The research involved 74 graduate students from a Dutch university, who were asked to write essays on controversial topics. Peers and ChatGPT were then used to provide feedback on these essays. Two coding schemes were employed to assess the quality of the essays and the feedback: one for essay quality and another for feedback quality. A MANOVA analysis was used to compare the feedback quality between peers and ChatGPT, while Spearman's correlation was used to explore the relationship between essay quality and feedback quality. The results showed a significant difference in feedback quality between peer feedback and ChatGPT-generated feedback. Peers provided higher quality feedback, particularly in identifying problems in the essays. ChatGPT, on the other hand, provided more descriptive feedback, including summaries of the essays. However, there was no significant relationship between the quality of the essays and the quality of the feedback provided by peers or ChatGPT. The study suggests that ChatGPT and peer feedback could complement each other in the feedback process, with ChatGPT offering more descriptive feedback and peers providing more problem-identification feedback. The findings indicate that the quality of essays does not necessarily influence the quality of feedback provided by either peers or ChatGPT. The study highlights the potential of ChatGPT as a feedback source, particularly for complex tasks like essay writing, and suggests that integrating ChatGPT with peer feedback could enhance the feedback process in higher education. The study also acknowledges limitations, including the narrow scope of the sample and the need for further research to validate these findings in broader contexts.This study investigates the quality of peer-generated feedback and AI-generated feedback (specifically from ChatGPT) in the context of essay writing. It compares the effectiveness of these two feedback sources in enhancing students' writing skills. The research involved 74 graduate students from a Dutch university, who were asked to write essays on controversial topics. Peers and ChatGPT were then used to provide feedback on these essays. Two coding schemes were employed to assess the quality of the essays and the feedback: one for essay quality and another for feedback quality. A MANOVA analysis was used to compare the feedback quality between peers and ChatGPT, while Spearman's correlation was used to explore the relationship between essay quality and feedback quality. The results showed a significant difference in feedback quality between peer feedback and ChatGPT-generated feedback. Peers provided higher quality feedback, particularly in identifying problems in the essays. ChatGPT, on the other hand, provided more descriptive feedback, including summaries of the essays. However, there was no significant relationship between the quality of the essays and the quality of the feedback provided by peers or ChatGPT. The study suggests that ChatGPT and peer feedback could complement each other in the feedback process, with ChatGPT offering more descriptive feedback and peers providing more problem-identification feedback. The findings indicate that the quality of essays does not necessarily influence the quality of feedback provided by either peers or ChatGPT. The study highlights the potential of ChatGPT as a feedback source, particularly for complex tasks like essay writing, and suggests that integrating ChatGPT with peer feedback could enhance the feedback process in higher education. The study also acknowledges limitations, including the narrow scope of the sample and the need for further research to validate these findings in broader contexts.