To keep pace with the increasing need of infrastructural development in the mountainous regions, several tunnels have been built for the highway and railway transportation systems. However, with increasing seismic activities, the damage of such tunnels has also been reported worldwide. So, the issue of protecting such tunnels against seismic activities needs to be addressed carefully. This chapter presents a brief review of the damage patterns of the tunnels in mountainous regions due to seismic hazards, focusing on damage characteristics and possible restoration methods. First, a wide collection of case studies has been reviewed from literature and then the damage types have been investigated. Various damage types of tunnels have been identified from the perspectives of tunnel body and portal. Next, the damage influencing factors have been investigated based on seismic parameters, geological conditions, and tunnel’s structural characteristics. Finally, some restoration methods and design criteria have been discussed briefly.