<p>Nuclear containment structures are heavily reinforced concrete buildings, functioning as airtight pressure-resistant vessels that serve as the final safety barrier in preventing the release of radioactive materials to the environment in the event of an accident. They act as the last line of defense against internal failures, such as loss of coolant accidents, reactor core meltdowns and their associated pressure build-ups, as well as natural external events like major storms, floods, projectile impact, and earthquakes. To ensure the long-term integrity of these structures against seismic events, in particular, fragility analysis is carried out to quantifying probabilistically the likelihood of the structural system or component falling below predefined levels of performance or exceeding certain damage thresholds. The analysis is performed relative to a variety of seismic intensity parameters, typically derived from historical or synthetic earthquake data, as well as different selection of materials, reinforcements, and structural degradation mechanisms. This article provides a critical review of current research into seismic fragility analyses of nuclear containment structures, exploring both the different methodologies used to investigate seismic fragility, such as probabilistic approaches, incremental dynamic analysis (IDA), and finite element modeling. It also examines hazardous conditions that influence the outcomes of these analyses, including concrete degradation, chloride-induced corrosion of embedded steel reinforcements, near- and far-fault ground motions, and internal pressure within the structure. The aim of the paper is to create a reference, supporting informed decision-making for risk management and structural design of future nuclear facilities.</p>