This study investigated the alignment of the General Education Diploma (GED) English exams with the Ministry of Education assessment framework as well as the washback effects of these exams in teaching English language from the perspectives of English language teachers. The sample consisted of eight versions of GED English Exams and 112 English teachers teaching Grade 12 in Muscat Governorate. Twelve of the 112 English language teachers were interviewed. Data were collected through content analysis forms, focused-group interviews, and questionnaires. The data analysis showed that the participants held similar perceptions regarding the alignment of the GED English exams with the MOE assessment framework and their washback effects in teaching English language. The content analysis forms revealed that the listening, grammar, and vocabulary questions in the GED exams highly align with the assessment framework, while there is a little alignment between the reading and writing questions in GED exams and the assessment framework. Additionally, the questionnaire and the focused group interviews showed somehow identical views on the alignment between the GED English exams and the assessment framework in some aspects. As for the teachers' perceptions, the results indicated no total alignment between the GED English exams and the assessment framework, and that there are some missing alignment aspects between them, such as the type of writing question, the number of words in the reading texts, and the topics in the writing and reading questions. The results further illustrated teachers’ agreement that there is a washback effect of GED English exams on teaching English language. They emphasized that the GED English exams have positive effects in their classes where they use them to train their students, give feedback, and highlight certain aspects related to the GED English exams. In light of the results, policy implementations were highlighted and further research recommendations were proposed.