In this chapter, we turn our attention to large-scale wireless networks and borrow tools from stochastic geometry to study the physical layer security performance. We consider the legitimate users and the eavesdroppers to be randomly located over a large geographical area according to some probability distributions. The network connectivity and throughput performance are discussed based on two analytical approaches. Specifically, the secrecy graph, as a graph-theoretic approach, is introduced to study the connectivity properties among the legitimate users of the network. It characterizes the existence of connection with perfect secrecy between any two legitimate users. The second approach is the development of a performance metric named secrecy transmission capacity. It considers concurrent transmissions between all the legitimate links and gives a mathematically tractable measure on the achievable network throughput with a given secrecy requirement.