In the realm of language education, the influence of learners' personality traits on their educational outcomes within novel instructional frameworks has gained prominence, prompting an exploration into the effects of ambiguity tolerance on grammar acquisition among English as a Foreign Language (EFL) students. This study investigates the impact of learners' personality traits on their learning outcomes in innovative instructional models, such as flipped and blended classes. A sample of 120 EFL students was divided into four comparative groups and two control groups based on their proficiency and ambiguity tolerance (AT) scores. The study utilized a Learning Management System (LMS) to deliver instruction to the different groups. The blended group received a combination of online and face-to-face instruction, while the flipped group received online instruction using the flipped approach. The control group received only face-to-face instruction. After a semester of instruction, a posttest on grammar learning was administered. The findings showed that the blended group performed better than the flipped and face-to-face groups in terms of grammar learning. The study also found no significant differences in grammar learning between high AT and low AT participants in the flipped and blended classes. However, high AT students in the face-to-face class demonstrated higher levels of success in grammar learning compared to low AT students.