Background and Purpose: Globally, many married adults engage in infidelity. However, the repercussions of the act appear not palatable for couples, their children and the society at large. This study therefore, investigated the aftermaths of infidelity as expressed by literate working class women in Lagos State. The study also examined whether age and type of marriage would affect the respondents’ views.   Methodology: The descriptive design was adopted for this study. A total of 300 literate working class women were drawn from the target population using purposive and simple random sampling techniques. A researcher-developed questionnaire tagged Aftermaths of Infidelity (AIQ) was used to collect data. The instrument was validated by five experts in Nigeria and Nusantara while its reliability was established through test re-test reliability method and a coefficient of 0.74 was gotten. The data collected were analyzed using t-test and Analysis of Variance (ANOVA) at 0.05 level.   Findings: Results showed that divorce, unhappiness, contact of sexually transmitted diseases, emotional disability, hatred in the family, unwanted pregnancy, distrust and suspicion in the family, psychological trauma in children, and giving birth to illegitimate children are some of the aftermaths of infidelity as expressed by the literate working class women. Similarly, age and marriage type did not influence the expression of literate working class women in Lagos State on infidelity.   Contributions: Infidelity has devastating aftermaths. Counsellors should enlighten couples on the aftermaths of infidelity; they should enlighten them on the negative effects which infidelity has on the home, children and the society in general.   Keywords: Aftermath, infidelity, literate working class women, Lagos State, Nigeria.   Cite as: Odebode, A. A., James, J. F., Adegunju, K. A., & Julia, J. (2021). Aftermaths of infidelity as expressed by literate working class women in Lagos State, Nigeria.  Journal of Nusantara Studies, 6(2), 41-57. http://dx.doi.org/10.24200/jonus.vol6iss2pp41-57