This thesis presents a study that investigated the teachers' implementation of grammar through writing instruction in one Higher Education College in Oman. To be able to answer the research questions, the study adopted qualitative grounded theory as design. Three teachers were recruited as participants for the study. Classroom observations and semi-structured interviews were used as methods of data collection. The analysis of classroom observation data involved the use of three grammar teaching models; whereas the analysis of interview data used the constructivist grounded theory model. The classroom observation data revealed that teachers did not use any grammar through writing teaching strategies, but relied mostly on inductive grammar teaching, with one teacher using a mix of both deductive-deductive strategies. It was found that writing was generally practiced to only write about daily routines using the present simple as grammar form, but without a focus on the grammar concept. The findings of the interviews revealed that teachers' understanding of grammar through writing was good with one teacher, but was lacking with the other two teachers. The interviews also revealed that the teachers believed that the role of grammar in teaching was important and that teaching grammar through writing was essentially helpful for students' learning. However, it was found that the teachers believed some challenges prevented them from implementing grammar though writing in their classrooms. These challenges according to them were: lack of knowledge, lack of training, classroom size, learners' low proficiency, preparations of grammar through writing, time constraints, and the policy for teaching grammar in the college. As a central category, it was found that the teachers believed grammar through writing was important, but that their classroom observations did not reflect these beliefs due to some challenges. Hence, it was concluded that there is a high degree of incongruence between the participants' understanding and beliefs of grammar through writing and their classroom practices because of the challenges that they faced in their institution.