Realization of memristors capable of storing and processing data on flexible substrates is a key enabling technology towards “system-on-plastics”. Recent advancements in printing techniques show enormous potential to overcome the major challenges of the current manufacturing processes requiring high-temperature and planar topography, which may radically change the system integration approach on flexible substrates. However, fully-printed memristors are yet to be successfully demonstrated due to the lack of a robust printable switching medium and a reliable printing process. Here, we realize an aerosol-jet-printed Ag/MoS2/Ag memristor in a cross-bar structure by developing a scalable and low temperature printing technique utilizing functional molybdenum disulfide (MoS2) ink platform. The fully printed devices exhibit an ultra-low switching voltage (0.18 V), a high switching ratio (107), a wide tuneable resistance states (10-1010 Ω) for multi-bit data storage, as well as a low standby power consumption of 1 fW and a switching energy of 4.5 fJ per transition set. Moreover, the MoS2 memristor exhibits both volatile and non-volatile resistive switching behaviours by controlling the current compliance levels, which efficiently mimic the short-term and long-term plasticity of biological synapses, demonstrating its potential to enable energy-efficient artificial neuromorphic computing.