My dissertation focuses on the impact of oil trade ties and network on political instability: democratization, civil war onset, and coups. Oil is an important resource to most states, while a few states, especially autocratic states, can produce and export it. This implies that the break of oil trade ties may strategically or economically damage oil-importing states more than oil-exporting states. In the three essays of my dissertation, I argue that oil trade ties allow oil-exporting states to resist to external pressures and encourage oil-importing states to support important oil exporters in order to avoid losing access to a much-needed commodity. In order to measure the effect of oil trade ties on three political instability problems, I employ centrality indices in weighted networks of network analysis. Based on the centrality indices, I measure the effect of oil-importing states on oil-exporters’ abilities to resist international pressures and to obtain external support, and examine how an oil-exporting state’s oil trade ties affect its three political instability phenomena: democratization, civil war onset, and coup risk. Empirical results reveal three ways in which an oil-exporting state’s oil trade ties might affect its political instability; an autocratic oil-exporting state’s oil trade ties reduce external democratizing pressures and hinder democratization; an oil-exporting state’s oil trade ties attract external prewar support for its government, and reduce the likelihood of civil war onset when the exporter experiences external prewar support for its government; an oil-exporting state’s oil trade ties reduce the likelihood of coup.