<p>For the assessment of vulnerability of reinforced concrete (RC) buildings, particularly irregular ones, requires robust methodologies due to increasing frequency and intensity of seismic events. Irregularities in building design such as plan or vertical irregularities, often leads to complex dynamic behaviour during seismic events, which may result in severe structural damage or failure. In this study, the performance of irregular RC buildings, which are usually more prone to damage during earthquakes because of their geometrical shape and slenderness ratio are assessed using probabilistic seismic vulnerability assessment (PSVA). With the objective to develop fragility curves which gauge the probability of multiple damage states under various seismic intensity levels, the analysis takes into consideration the non-parallel lateral force system (NPLFS) type of plan irregularity along with different height models that significantly influences their seismic performance. The results suggest that NPLFS irregularity in reinforced concrete buildings are significantly performing good than as compared to regular models. Additionally, it emphasizes areas where design changes or retrofitting could enhance resilience and illustrates the effectiveness of probabilistic approaches in improving the precision of seismic hazard evaluations for irregular RC buildings. Due to the assessment being probabilistic, it helps stakeholders in understanding risk and make informed choices regarding disaster preparedness and safety of buildings. The PSVA framework can assist engineers and policymakers in implementing effective strategies for risk reduction by offering a quantitative foundation for assessing vulnerability. This ultimately contributes to creating a safer urban environment in regions prone to seismic activity.</p>