Introduction: Sexual abuse is a global public health problem that cuts across social class, cultures, tribes etc. and has permeated the fabrics of tertiary institutions and many work places as long as humans have reasons to interact. Aim: To determine the prevalence, pattern and determinants of sexual abuse among undergraduates in tertiary institutions in Imo State, Nigeria. Methodology: This study was a descriptive, cross sectional survey of 600 female students in tertiary institutions in Imo State Nigeria. They were selected using the multistage sampling technique and data were collected using a pretested, semi-structural and self-administered questionnaire and analyzed using a computer software (EPI INFO version 3.3.2). Descriptive statistics was presented using summary indices, frequency tables and percentages. Associations between variables were done using the chi-square and logistic regression. A p-value of less than 0.05 was considered significant. Results: The mean age of the respondents was 21.7 + 3.2 years. The current and lifetime prevalence of sexual abuse among the respondents was 15.2% and 34% respectively and the commonest form of sexual abuse experienced was founding/grabbing of sensitive body parts (52.5%). Factors found to influence current occurrence of sexual abuse among the students were; age (p = 0.010), tribe (p = 0.008), marital status (p < 0.001), type of student in secondary school attended (p = 0.001), faculty of study (p = 0), year in school (p < 0.0001), persons currently shared room with (p < 0.0001) and level of knowledge about sexual abuse (p = 0.007). Conclusion: The prevalence of abuse as revealed in this study was high. There is need to develop appropriated prevention strategies by the universities to curb this menace against our women.