Abstract: Background: Nigeria is considered the most populous country in Africa with an estimated population of 18 I million and a median age of I 7.9. Nigeria's young population indicates that fertility rate may l‹eep increasing with the total population increasing exponentially. However, life expectancy in Nigeria is very low accompanied by high mortality rate. Data Source and methods: This study aimed at analysing Nigeria's demographic data and presenting how Nigeria's overpopulation is contributing to its low life expectancy. Secondary quantitative data from United Nations Population Division was analysed for the study. Results: Findings showed increasing population growth from I 08,0 I I ,465 recorded in 1995 to 200,963,599 recorded in 2020, high fertility, high mortality rate and low life expectancy at 53 years. Conclusion: The study made recommendations on policies to regulate Nigeria's population growth and increase life expectancy of the country. Keywords: Demography, Life expectancy, Birth rate, Death rate, overpopulation