Lateness to school is a behavioural issue that causes major scholastic difficulties for both students and educators. This study, therefore, investigated the effect of Academic Values Clarification technique on lateness to school among secondary schools students in Awka South Local Government Area. One research question and one null hypothesis guided the study. Quasi-experimental research was adopted in carrying out the study. A sample size of 109 adolescents was chosen from a population of 355 students with records of habitual lateness to school. The sample was derived from three schools selected using the purposive sampling technique based on the schools that recorded a higher number of students that are chronic late-comers. The instrument, Observation Guide was used for data collection. Data relating to research questions were arranged in tabular form and used in answering the research questions while data relating to hypotheses were analysed using Analysis of Covariance (ANCOVA). Findings from the study revealed that Academic Values Clarification technique was effective in modifying lateness behaviour and reducing the magnitude of lateness among secondary school students. The findings further revealed that the effect of the Academic Values Clarification technique in modifying lateness behaviour among secondary school students was significant. Based on the findings, recommendations were made that the Academic Values Clarification technique is an effective technique for modifying students’ lateness behaviour for practicing counsellors. As a result, practicing counsellors should employ the strategies while counselling secondary school children to avoid lateness.