This study explores the impact of AI tools on improving students' academic writing skills in Vietnam. English is a key subject in Vietnamese education, and writing is considered a complex skill that requires careful teaching. AI tools have been integrated into education, and their use in academic writing has shown significant benefits. However, some studies suggest that AI tools may lead to issues such as plagiarism and laziness. In Vietnam, education has benefited from technology, especially during the pandemic, but teachers and students are hesitant to use AI due to its novelty and perceived complexity. Academic writing is characterized by formality, clarity, and precision. It requires students to develop skills in coherence, cohesion, grammar, and vocabulary. This study used action research to investigate the effects of AI tools on students' academic writing skills. The study involved 5 teachers and 60 students in two language centers in Hanoi. AI tools such as Grammarly and Quillbot were used to provide feedback and suggestions. The study found that AI tools significantly improved students' academic writing skills, particularly in coherence, cohesion, and lexical resources. Students also showed improvement in grammatical accuracy and range. The study also found that the frequency of AI tool use was positively correlated with students' writing scores. However, the study acknowledges the potential negative effects of AI, such as over-reliance on technology and reduced critical thinking. Overall, the study concludes that AI tools have a positive impact on academic writing, but further research is needed to fully understand their long-term effects.This study explores the impact of AI tools on improving students' academic writing skills in Vietnam. English is a key subject in Vietnamese education, and writing is considered a complex skill that requires careful teaching. AI tools have been integrated into education, and their use in academic writing has shown significant benefits. However, some studies suggest that AI tools may lead to issues such as plagiarism and laziness. In Vietnam, education has benefited from technology, especially during the pandemic, but teachers and students are hesitant to use AI due to its novelty and perceived complexity. Academic writing is characterized by formality, clarity, and precision. It requires students to develop skills in coherence, cohesion, grammar, and vocabulary. This study used action research to investigate the effects of AI tools on students' academic writing skills. The study involved 5 teachers and 60 students in two language centers in Hanoi. AI tools such as Grammarly and Quillbot were used to provide feedback and suggestions. The study found that AI tools significantly improved students' academic writing skills, particularly in coherence, cohesion, and lexical resources. Students also showed improvement in grammatical accuracy and range. The study also found that the frequency of AI tool use was positively correlated with students' writing scores. However, the study acknowledges the potential negative effects of AI, such as over-reliance on technology and reduced critical thinking. Overall, the study concludes that AI tools have a positive impact on academic writing, but further research is needed to fully understand their long-term effects.