The current study aims to examine Omani English language teachers' use of their learners' Li in L2 classrooms. The study takes as design a mix of qualitative case study and grounded theory research. The participant sample consists of three Omani English male teachers from Cycle Two Schools in Al Dahira Governorate in Oman, Data is collected through interviews and classroom observations. Qualitative content analysis is employed to analyze observations; while Charmaz's constructivist grounded theory is used to analyze the interview data. The findings of the study reveal that the teachers' use of learners' LI in the observed classes is significantly high as it is found that the teachers' average use of Li is 28% of their classroom discourse. However, at the same time, it is found that the teachers have demonstrated a high degree of understanding of the disadvantages of overusing Ll; of the optimal amount of L1; and of the different avoidance strategies that minimize the use of Li in L2 classrooms. Hence, the study concludes that the teachers' shift to L1 is shaped by the challenges they face in their classrooms rather than by their understanding. These challenges are found to be a lack of teaching materials, time constraints, a lack of teaching experience, class size, the learners' low level of proficiency in English, the teachers' lack of training, the types of activities used, and the heavy syllabus. Based on these findings, the study makes some recommendations on how to improve the situation of English language teaching in Oman vis-a-vis this educational phenomenon.