The study examined the influence of harmful widowhood practices on academic achievement of secondary school students in Nigeria: implications for Guidance. The study was guided by it one specific objective, one research question and two null hypotheses. The research design for this study was a descriptive survey research design. The population of this study comprised of all secondary schools in Nigeria. A sample size of three hundred and seventy (370) respondents was sampled for the study. The instrument was a self-designed questionnaire titled “Influence of Harmful Widowhood Practices on Academic Achievement Questionnaire (IHWPAAQ). Frequency counts and percentages was used to analyse the demographic data while Mean scores and Standard Deviations was used to answer the research questions also ttest was used to test the hypotheses. The study revealed among others that harmful widowhood practices play key role on students’ academic performance as well as their academic achievement as the practices often leads to depression, substance abuse, emotional abuse among others which often lead to low self-esteem, gender inequality and school dropout. The study recommended among others that the Counsellors and other stakeholders in education should make more efforts to provide adequate counselling services for victim of harmful widowhood practices in order to bring to the barest minimum the negative influence it has on students, this effort should be irrespective of gender or location.