Increasing evidence suggests that dysregulation of long non-coding RNAs (lncRNAs) is implicated with chemoresistance in cancers. However, their function and molecular mechanisms in gastric cancer (GC) chemoresistance remain not well elucidated. In this study, we aimed to investigate the functional role and the underlying molecular mechanism of lncRNA prostate cancer-associated transcript 1 (PCAT-1) in cisplatin (DDP) resistance of GC. Our results revealed that PCAT-1 was up-regulated in DDP-resistant GC tissues and cells. GC patients with high PCAT-1 expression levels had a poor prognosis. Knockdown of PCAT-1 facilitated the sensitivity of DDP-resistant GC cells to DDP. Additionally, PCAT-1 functioned as a sponge of miR-128 in GC cells. Moreover, inhibition of miR-128 reversed the inductive effect of PCAT-1 knockdown on DDP sensitivity of GC cells. In addition, ZEB1 was identified as a target of miR-128, and overexpression of ZEB1 could block the inductive effect of PCAT-1 knockdown on DDP sensitivity of GC cells. Besides, PCAT-1 knockdown enhanced DDP sensitivity in tumors in vivo. In summary, PCAT-1 confers DDP resistance in GC cells through miR-128/ZEB1 axis, providing a promising therapeutic strategy for GC.