The study examined the Causes of Marital Conflict and Its Effect on Academic Performance of Married undergraduate students in Abia State Universities. Five (5) objectives, 5 research questions and 5 hypotheses guided the study. Descriptive survey design was used in the study. The population of the study consists of all the married undergraduate students in Abia State Universities with a total population size of 180 students. Census was used to engage all the population 180 married undergraduate students (126 males and 216 females) in Abia State University. The instrument used for data collection was a self-structured questionnaire. The instrument was titled “Causes of Marital Conflict and Its Effect on Academic Performance of Married Undergraduate Students Questionnaire”. The instrument was validated by the research supervisor and two other experts in Measurement and Evaluation, Faculty of Education. The internal consistency reliability through Cronbach Alpha was used to establish the reliability of the instruments which obtained a reliability coefficient of 0.77. The data gathered were analyzed using descriptive statistics, mean and standard deviation for the research questions, while the null hypotheses were tested using z-test statistical tool. The findings of the study revealed that infertility, physical abuse, external pressure, financial problem and communication problem have effects on the academic performance of married undergraduate students in Abia State Universities. However, the study recommends that government through the community town hall meeting should enlighten parents on how to manage infertility with social and academic performance of married undergraduate students among others.