This quasi-experimental study examined the effect of the flipped classroom strategy (FCS) on the grammar learning of female Omani grade eleven students as well as their motivation toward learning English. In total, 72 female students attending one public school in A’Seeb, Muscat Governorate, in the 2023/2024 academic year participated in the study. One class of 37 students was assigned as an experimental group and was taught using the FCS, whereas another class of 35 students was taught the same grammatical structures using conventional teaching methods as a control group. Two instruments were utilized to collect data: a pre- and post-grammar achievement test and a motivation questionnaire. The results showed a statistically significant improvement in the experimental group’s grammar performance. There were also statistically significant differences between the mean scores in the post-test in favor of the experimental group. However, there were no statistically significant differences in motivation toward learning English before and after applying the FCS. In light of these findings, the study concludes with some implications and recommendations for further research.