Energy consumption and latency are two major problems that are primarily considered in the design of medium access control (MAC) protocols in wireless sensor networks (WSNs). A new low-latency, energy-efficient and receiver-initiated asynchronous MAC protocol in WSNs is proposed. By precisely predicting the receiver’s wakeup time, THO-MAC protocol can schedule the sender to listen to the channel, such that it can reduce the sender’s energy waste of idle listening. On the other hand, in order to reduce packet delivery latency, THO-MAC protocol chooses the forwarders in the sender’s two-hop forwarders set to minimize the two-hop forwarding latency. The performance of THO-MAC protocol in terms of detailed NS2 simulation is evaluated. The simulation results show that the THO-MAC protocol reduces 35.5% and 18% packet delivery latency, while saving 23.5% and 15.5% sensor energy consumption, compared with RI-MAC and Any-MAC, the two state-of-the-art MAC protocols.