Studies on automated written corrective feedback have shown how it can help improve students’ overall writing performance. Nonetheless, it has also been found that the improvement is not always significant, especially when compared to traditional feedback provided by the teachers. Considering that there have been contradicting results regarding the effectiveness of automated written corrective feedback in improving learners’ writing, this study is aimed at exploring how Grammarly affects undergraduate EFL students’ writing performance, more specifically their grammar, spelling, capitalization, punctuation, and vocabulary. This research employs an experimental design as it seeks to examine the effectiveness of utilizing Grammarly in improving students’ writing. The respondents for the current study are second-semester students of the English Department at Bunda Mulia University. They have been selected for this research as they are all currently taking the Writing 1 subject and their overall English writing proficiency range from novice to intermediate, meaning that most of them still tend to make some grammatical, spelling, capitalization, punctuation, and vocabulary errors in their writing. The students are divided into two groups, namely the control group, in which the students receive feedback from the lecturer, and the experimental group, in which Grammarly is employed. The paired samples T-test is used to analyze the result of the pretest and posttest from both groups and the data is calculated using the SPSS version 23 software. The result of both groups is compared to find out whether Grammarly is more effective in comparison to the traditional feedback given by the lecturer. In addition, the students are asked to fill out a questionnaire regarding their perception of the feedback from Grammarly and their lecturer. The result of the questionnaire for both types of feedback is also compared to see which of the two are considered more beneficial for them. The findings of the study reveal that between the feedback provided by the lecturer and the feedback from Grammarly, the latter is more effective in improving the students’ writing. In addition, the students from both groups generally have a positive view of the necessity of the feedback and feel that they are more or less able to improve their writing after receiving the feedback, either from the lecturer or from Grammarly.