Mobile phones have become an increasingly important part of our lives, especially in recent years due to the COVID-19 pandemic, particularly among students. Since the beginning of the pandemic, we have witnessed a series of lockdowns that prevented us from communicating with the outside world, leaving us with only a phone as the means of communication. In a matter of days, schools and colleges went online, increasing students’ mobile usage. The present study was conducted to understand the mobile usage behaviour among agricultural students of Tamil Nadu Agricultural University, during COVID-19. Empirical data was collected from 60 students using a structured interview schedule. Findings revealed that students used their mobile phones for more than 8 hours a day during the lockdown. Video conferencing apps like Microsoft Teams, Google classroom, etc. were used more frequently, followed by social networking apps. Age showed a significant and positive correlation with mobile usage behaviour at 0.05 level of probability whereas, education, social media addiction, monthly expenditure, and internet usage were found to exhibit a positive and significant correlation with mobile usage behaviour at 0.01 level of probability.