<p>Oil spillages have been a significant environmental, health, social, and economic challenges in Nigeria over a decade. Extreme value analysis of oil spills in Nigeria is essential due to the increasing frequency and severity of spill incidents, which are exacerbated by factors such as pipeline vandalism, operational failures, and environmental degradation. The aim of this paper is to perform the first extreme value analysis on daily oil spill measurements from eight stations in Nigeria. Quarterly maxima of the daily data are used to identify extreme values, which are modelled using the generalised extreme value distribution. Two of the model’s three parameters are allowed to vary linearly, quadratically, or in combinations with the quarter number. The Kolmogorov-Smirnov test evaluates model fit. Significant upward trends in quarterly maxima are observed at four stations, including those in Uyo, Lagos, and Kaduna. The trends for Uyo and Lagos reach maxima in 2008 and 2012, respectively. The trend for Kaduna reaches a minimum in 2015. These trends, none of which are decreasing, are expected to worsen environmental degradation, damaging ecosystems like mangroves and farmlands, polluting water sources, and aggravating public health issues. This will heighten poverty, fuel social unrest, and threaten economic stability and international investments.</p>