This research study investigated the effectiveness of Rational Emotive Behavior Therapy (REBT) on depression and anxiety during the coronavirus disease 2019 (COVID-19) pandemic in Nigeria. REBT is used in correcting irrational beliefs and behaviors. This study adopted a randomized pretest, post-test, control group design. Two trial-tested instruments covering; depression, anxiety, and irrational beliefs were for data collection. Data obtained with the instruments were analyzed using mean, standard deviation, and analysis of variance. The study revealed that REBT was effective in reducing depression and death anxiety in COVID-19 patients. The result of this study also showed that the introduction of REBT helped to curb the spread of COVID-19 disease by letting Nigerians to know that the existence, mode of spread, and consequences of the disease is real and not a myth., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)