Abstarct: Despite all the advantages of AI, there is a gap in the body of knowledge on integrating AI to enhance the flipped classroom approach to teaching grammar to EFL students. The present study, drawing on quasi-experimental, made an attempt to fill in the gap by investigating the effect of using AI- mediated flipped classroom approach to teach grammar on EFL students' grammar achievement. Ninety language learners at elementary level in an English institute were selected as the participants through convenience sampling. While individual students weren't randomly assigned, the entire classes were randomly assigned to the three experimental conditions: 1) flipped classroom approach only, 2) AI-mediated instruction only, 3) AI mediated flipped classroom. The instruments used in the current study consisted of a pre-test and a post-test. Participants of all groups took the pretest of the intended grammatical structures. Then, all groups went through 13 sessions of 30-minute instruction focusing on teaching grammar. The flipped method group students were taught grammar using the traditional flipped classroom method, AI-mediated group were taught using AI in the classroom while the third group students received instruction through an AI-mediated flipped classroom approach. After completing the treatment, the participants of all groups were given a post-test on intended grammatical structures. Data were analyzed using descxriptive and inferential statistics, including Multivariate Analysis of variance (MANOVA), Univariate Analysis of Variance (ANOVA) (Tests of Between-Subjects Effects), Post Hoc Comparisons (Tukey’s Honestly Significant Difference). The results of tests showed that AI-mediated flipped classroom approach has a positive effect on participants’ grammar achievement and the necessity and efficiency of using them in EFL classes, especially in the case of grammar teaching.