The seismic performance of tunnels in the Indian Himalayas, a seismically active region, is a critical concern due to the complex geological conditions. Although tunnels are generally considered safer under seismic loads, recent tunnel collapses have redirected focus on this area. This study explores the impact of varying ground conditions on tunnel behavior during seismic events. Using finite element modeling, a typical horse-shoe-shaped tunnel is analyzed under two rock mass conditions. A visco-elasto-plastic model with Hoek–Brown yield criterion is adopted to capture the nonlinear behavior of rock deposits under seismic excitation. A nonlinear dynamic analysis is performed to observe the seismic behavior of the tunnel in terms of forces generated in the tunnel lining. Analysis of the results shows that tunnels in good rock mass tend to be much safer than tunnels in poor rock mass conditions.