Content knowledge is one of the Shulman’s teacher knowledge. In no small measure, content knowledge promotes learning and contributes to students’ learning outcomes. The knowledge of what to teach is a key requirement for effective teaching. This paper assesses the subject matter knowledge that Literature-in-English teachers possess and reveals subject content areas where Literature-in-English teachers exhibit high mastery. This paper examines whether teachers’ content knowledge could predict students’ achievement in and attitude to Literature-in-English. The study is a descriptive research of the survey type. Data were collected through the use of four research instruments: classroom observation scale, classroom content knowledge checklist, self-constructed students’ questionnaire and an achievement test. Data collected were analyzed using descriptive and inferential statistics. The participants of the study consisted of 632 students who offered Literature-in-English and 127 Literature-in-English teachers. Findings revealed that the observable elements where mastery was shown are knowledge of literary works and literary appreciation skills. However, the study showed that Literature-in-English teachers did not have sufficient mastery of language development and knowledge of values. The findings show that teachers’ content knowledge predicted students’ learning outcomes (achievement and attitude) in Literature-in-English. The findings raised concerns about pedagogical implications and recommendations for concerned education stakeholders.