This special issue contains a collection of six papers dealing with the geology, geophysics, and tectonics of Taiwan and the Philippines. Most of these papers were presented at the fourth “Philippines-Taiwan Earth Sciences International Conference” in Manila, Philippines, 8 - 9 June 2013. The tectonics of Taiwan and the Philippines are controlled mainly by three plates: the Indian, Eurasian, and Philippine Sea Plates. Taiwan and the Philippines are located next to each other in terms of geography and also plate tectonics. Luzon Island originated from the interactions between the South China Sea and Philippine Sea Plates. Taiwan was also created by collisions between the Philippine Sea Plate and Eurasian Plates. The convergence of these plates also results in many earthquakes and volcanic activities in the region. Both Taiwan and the Philippines face similar geological hazards, such as earthquakes, landslides, volcanic eruptions, and tsunamis.