This study explores the acceptance and use of WhatsApp messenger for teaching and learning in senior high school during the COVID-19 pandemic period. This research adapted TAM as its theoretical model. The participants of the study were 62 history students from a senior high school in Ghana. The study also adopted a questionnaire as the research instrument. The data collected from the participants were then analysed using the Pearson Product-Moment Correlation analysis. The results from the study show that ease of use of WhatsApp Messenger, usefulness of WhatsApp Messenger, technological challenges, and student attitude towards WhatsApp Messenger use determines students’ actual WhatsApp Messenger use in teaching and learning. Additionally, the study found that student attitude performed a mediating role between ease of use, usefulness, and technological challenges on the one hand and student actual WhatsApp use on the other hand. It was suggested that future studies consider structural equation modeling using the same conceptual model adapted for this study. Also, high school authorities should consider equipping school libraries with m-learning technologies to facilitate teaching and learning.