The present qualitative case study investigated the beliefs and practices of six English language teachers in secondary schools in Oman about grammar instruction. To improve EFL education in Omani schools, the study sought to determine whether teachers' beliefs and their grammar teaching practices were congruent. The study collected the data through classroom observations and interviews, and analysed the data using content analysis and Grounded theory to analyze the data. The findings showed that even though most teachers acknowledged the benefits of inductive grammar instruction, they favored deductive grammar instruction. Teachers attributed their classroom decisions to various factors such as students' language proficiency, time constraints, and curriculum overload. In addition, the findings showed that teachers' learning experiences shaped their decision-making and instructional practices. The lack of professional development training was another crucial factor that influenced their beliefs and grammar teaching practices. The study concluded that teachers in Oman required more individualized training sessions that could foster alternative beliefs and practices in favor of inductive grammar instruction.