Background: COVID-19 is in the family of the Coronaviruses. Coronavirus is one of the main pathogens that fundamentally aims at the human respiratory system.

Objectives: This study predicted the COVID-19 transmission in Nigeria via the adjusted SIR model.

Methods: An adjusted SIR model was applied to the NCDC daily data spanning from 27^th February 2020 to 7^th May 2020.

Results: Susceptible, infective, and recovered individuals were identified with their corresponding trend lines. There were higher occurrences of infected persons, the infective series reached its peak at day 122 with a total of 77,009,941. The infective line began to tail off after day 122 while the recovered began to rise and the susceptible also tailed off gradually. The COVID-19 pandemic was predicted to last for 422 days from the day of its inception in Nigeria.

Conclusion: The findings in the study capitalizes more on the need to adhere strictly to the COVID-19 laid down rules so as to stay safe.