Inkjet-printed　indium-tin-oxide　(ITO)　synaptic　thin-film　transistors　(TFTs)　using　solution-processed　high-k　zirconium　oxide　(ZrOx)　gate　dielectric　layer　are　reported.　The　effect　of　ZrOx　annealing　temperature　from　300　to　500　°C　on　the　TFT　performance　is　investigated.　The　optimized　ZrOx　gate　dielectric　layer　of　the　ITO　TFT　can　mimic　biological　synaptic　response　for　the　realization　of　intelligent　computers　and　artificial　bionic　brain.　The　strong　synaptic　behavior　of　the　ITO　TFT　exhibiting　the　on/off　current　ratio　of　≈106　can　be　obtained　at　the　ZrOx　annealing　temperature　of　300　°C.　The　amount　of　hydroxyl　(-OH)　groups　in　the　dielectric　film　can　be　a　crucial　factor　for　the　formation　of　an　electric　double　layer　(EDL)　on　the　top　region　of　the　gate　dielectric.　The　device　exhibits　the　excitatory　post-synaptic　current　(EPSC),　inhibitory　postsynaptic　current　(IPSC),　and　paired-pulse　facilitation　(PPF).　Therefore,　the　inkjet-printed　ITO　TFT　using　printed　ZrOx　gate　dielectric　can　be　used　for　low-cost　synaptic　TFTs.　©　2020　Wiley-VCH　GmbH