The study aimed to establish the effect of secondary school guidance programs in preparing students for successful transition to university. Mixed methods research design was used which included the use of both quantitative and qualitative methods to generate data using a concurrent triangulation approach. Purposive sampling was applied to sample first year students in Moi University and proportionate sampling together with simple random sampling was used in the selection of 375 participants comprising both male and female students. Data were collected through questionnaires and focus group discussions. Quantitative data were analyzed using descriptive (mean and standard deviation) and inferential statistics by means of SPSS (Pearson Correlation Coefficient), followed by linear regression to test the hypothesis. Thematic analysis was used for qualitative data analysis. The findings of this study revealed that high school guidance programs do not support learners adequately in preparing them to transition to university. The study recommended the implementation of more enhanced collaboration between schools and universities for successful transition.