Reinforced concrete (RC) highway bridges are critical components of transportation networks, facilitating regional connectivity and economic development. In recent years, the frequency of earthquakes has increased globally. Historical seismic events have demonstrated that earthquakes often occur in sequences, whereby a mainshock (MS) is typically followed by aftershocks (AS). Numerous post-earthquake reports have documented significant damage to RC highway bridges under these MS-AS sequences. Catastrophic consequences were observed in events such as the 1987 Whittier Narrows, 2016 Central Italy, and 2023 Turkey earthquakes. In these cases, significant aftershocks contributed to cumulative bridge damage, disrupting their normal operation, delaying their recovery, and ultimately reducing their seismic resilience. Given the randomness of seismic events, bridges may experience multiple earthquakes over their life-cycle, rendering it crucial to assess their seismic resilience from a long-term perspective. Such assessments are vital for making informed decisions regarding bridge maintenance and management. Additionally, as bridges progress in service, they are subject to corrosion-induced deterioration, which further exacerbates damage and diminishes resilience. However, there is a notable lack of research on the long-term resilience assessment of aging RC highway bridges considering the influence of aftershocks. To address this gap, this study proposes a method for estimating the long-term seismic resilience of deteriorating structures. Three multi-span RC highway bridges with varying geometries are selected as benchmarks, and detailed finite element models are developed for them. A suite of 80 pairs of ground motion sequences is selected, and nonlinear time history analyses are conducted on the bridge models. The cumulative damage to the bridges is quantified using the Park-Ang damage index. Based on this, the long-term seismic resilience of the benchmark bridges is determined using the proposed method, and the influence of aftershocks on the long-term resilience is investigated. The results indicate that the effect of aftershocks on long-term seismic resilience depends on several interrelated factors, including the relative intensity of the mainshock-aftershock sequence and the dynamic characteristics of the bridges, and is only marginally influenced by seismic intensity.