vAssessment is any of variety of procedures used to obtain information about students’ performance. It is a general term that includes the full range of procedures used to gain information about students’ performance in learning including project, observation, and paper based assessment. Content validity aspect means that a test measure the appropriate content based on the objective that teachers are measuring. This research aims to analyze the quality of English formative assessments made by teacher in SMP Al-Irsyad Al-Islamiyyah Purwokerto based on the aspect of content validity. The researcher analyzed the quality of English formative assessment based on the aspect of content validity and described the conformity of English formative assessment to the syllabus. This research was descriptive qualitative research. The primary sources of this research was the scriot of English formative assessment for 8th grade in SMP Al-Irsyad Al-Islamiyyah Purwokerto, and was added by another source from the interview with the teacher. The researcher used interview and documentation as the technique of collecting data. The techniques of analyzing data were identification, explanation and calculation. The result of the research was the percentage and the explanation of content validity of the English formative assessment in SMP Al-Irsyad Al-Islamiyyah Purwokerto. According to the analysis that the researcher did, the quality of English formative assessments based on content validity aspect was good (80%) and very good (100%). From four assessments that the researcher analyzed, there were three assessments that contained some questions that did not conform to the indicator in the syllabus.