Systems and methods for determining signal source location in wireless local area networks are disclosed. An example method includes receiving, from a first signal reader, a first time-of-arrival measurement for a first radio frequency (RF) signal generated by a first wireless local area network (WLAN) signal source located at a first known location, the first time-of-arrival measurement being relative to a first clock of the first signal reader; receiving, from a second signal reader, a second time-of-arrival measurement for the RF signal, the second time-of-arrival measurement being relative to a second clock of the second signal reader, wherein the first clock is not synchronized with the second clock; defining a first time relationship between the first clock and a system time based on the first time-of-arrival measurement; and defining a second time relationship between the second clock and the system time based on the second time-of-arrival measurement.