"Where You Sit Matters: Diplomatic Networks and International Conflict" examines how a state's structural position within diplomatic networks influences its foreign policy behaviors, particularly in the domain of international security. Despite the established understanding in International Relations (IR) that relationships among countries matter, there is little empirical knowledge on what exactly the complicated web of those relationships looks like and how it impacts state behavior. Much IR literature tends to focus only on dyadic or multilateral relationships and treat networks as background, which has left a gap in our understanding of how the structures of international networks affect international outcomes. To address this gap, my dissertation uses network analysis and a variety of statistical methods to reveal key structures of diplomatic networks and examine their impacts on a state's foreign policy behavior. My argument extends in three directions. The first part uses a large-n, cross-sectional analysis to examine the impacts of a state's broker position within diplomatic networks on its decision to initiate and escalate militarized interstate disputes (MIDs). By using the rare events logit and Heckman selection models, I find that occupying a broker position in diplomatic networks increases a state's decision to initiate MIDs over the nearly 200-year period from 1817 to 2001; its marginal impact is nearly twice that of military capability. The second part employs a separable temporal exponential random graph model (STERGM) to examine how key structures of diplomatic networks influence a state's decision to terminate diplomatic ties. My findings show that the breakdown of diplomatic ties is not a rare event and network dynamics play a role in terminating ties: states take cues from other countries in the network to decide whether or not to terminate diplomatic ties. The last part uses a community detection method, specifically a link communities method, to reveal latent communities of the diplomatic network and identify key countries that belong to multiple communities. I find that the diplomatic network resembles a hierarchical structure in that diplomatic communities tend to overlap; only a small number of major powers simultaneously belong to multiple communities and few communities are independent from those major powers.